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Full text of "The Danish Ingolf-expedition"

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/ 



THE DANISH 



I N Cx O L F- E X P E D HI O N. 



:h- 



VOL. V B. 



PUBLISHED AT THE COST OF THE GOVERNMENT 



THE DIRECTION OF THE ZOOLOcllCAL MUSEUM OF THE UN'IVERSITY. 



-1^ 



COPENHAGEN. 

H. HAGERUP. 

PRINTED BY BIANCO LU N O A/S. 
1914-1919- 




QL 
b 

D3 



Contents of Vol. V b. 

V. Hj. Broch: Stylasteridae, p. 1-25 (5 plates), 1914. 
VI. Hj. Broch: Hvdroida, I, p. 1-66 (2 plates), 1916. 
VII. Hj, Bruch: Hvdroida, II, p. 1-206 {1 plate). 191S. 
VIII. P. L. Kramp: Medu.sa;', I, Leptomedusa?, p. 1-111 (5 plates), 1919. 



THE DANISH INGOLF-EXPEDITION. 



VOLUME V. 



STYLASTERIDAE. 



BY 



HJALMAR BROCH. 



WITH 5 PLATES AND 6 FIGURES IN THE TEXT. 






COPENHAGEN. 

PRINTED BY BIANCO LUNO. 
I914. 



CONTENTS. 

Stylasteridae. 

Page 

Introduction i 

The Stylasteridae of the North Atlantic 3 

Pliohothrus Pourtales 3 

Pliobothrus symmetricus Pourtales ^ 3 

Stylasier Gray 7 

Sty taster gemmascens (E s p er) 8 

— roseiis (Pallas) 12 

— norvegiais (G u n n e r u s) 15 

Remarks on the affinities and systematic position of the Hydrocoralliucs ig 

Zoogeographical remarks ou the North Atlantic Stylasteridae 22 

Literature 



Introduction. 



The close examination of the Hydrocorallines meets perhaps with more difficulties than the 
study of the skeleton-bearing Hexacorallia, owing partly to the porous skeleton of the colonies, 
partly to the delicate nature of the organisms. The characteristics can be determined roughly by 
means of Dr. Koch's detailed method in which thin sections of the colonies are prepared by grinding 
with the stained soft parts in situ. The structure of the skeleton can also in part be studied by 
breaking the colonies as Hickson (1912 p. 891) seems from the following remark to have done. "The 
way in which it is possible to study the shape of the gasteropore styles is to make a vertical fracture 
in a plane parallel with the long axis of a branch. In a large percentage of such fractures the whole 
length of at least one gasteropore with its style will be exposed". It is evident however, that this 
method is not suited to form the base of a more thorough and systematic investigation of the skeletal 
parts of the colony. Where it is necessary for tlie observer to make his results free from chance 
irregularities he must have recourse to the somewhat slower method of grinding. In the present 
studies this latter method has throughout been used in the examination of the skeleton. The soft 
parts are first removed by means of Eau-de-Iyabarraque, and pieces of the colony have then been 
ground down on a fine and level whetstone as far as seemed necessary in each single case. For 
general systematic work it is usually sufficient to grind down a branch to about its median longi- 
tudinal plane; in a Sty/asfcr^ for example, the majority of the gasterostyles will in most cases 
appear quite free in the middle of the gasteropore. On the finely polished ground surface it will also 
be possible to study the course of the fine canals. Where there is question of examining the finer 
structure of the calcareous skeleton, however, this procedure is not sufficient and it is necessary in 
addition to have thin sections of the same kind as the geologists use in their studies. 

Since Moseley's fundamental work on the Hydrocorallines appeared in 1881 investigators have 
mainly directed their attention towards unravelling the features of the skeleton of the colonies. Ex- 
cluding a couple of smaller papers on the gonophores of a few species, no observer since that time 
has sought to penetrate deeper into the organisation and finer structure of the Hydrocorallines. The 
result is, that we cannot yet be said to have full knowledge of their affinities and thus of their syste- 
matic position, a matter I shall return to later. — On studying Moseley's work we see at once, that 
none of the species hitherto found in the northern seas have been closely investigated; as will 
be shown in the following; even their specific characters have been more or less imperfectly 

The Ingolf-Expcililioii. V. j. ^ 



STYLASTERIDAE 



Studied. It was thus of the highest importance to examine the soft parts of the northern H\dro- 
coralHnes more thoroughly; as Pax correctly remarks in a recent work on stony corals (1910 p. 65), "wir 
diirfen uns nicht verhehlen, dass jede Art, von der nur das Skelett vorliegt, als unvollstandig bekannt 
gelten muss, gleichgiltig, ob ihr anatomischer Ban fiir systematische Zwecke verwendbar ist oder nicht." 
It appears from the investigations, that the least injurious solution with which to remove the 
calcareous constituents is that recommended by Pax (1910 p. 71): 100 parts 70% alcohol, 10 parts con- 
centrated nitric acid and 2 parts concentrated, aqueous phloroglucine solution. In small pieces of the 
colony the calcareous parts are usnalh- completely removed during about 12 hours; larger pieces have 
sometimes to remain in the liquid up to 48 hours before all the carbonate of lime is removed. The 
coarser structure is then studied most easily by means of thick celloidin sections, the finer by means 
of thin paraffin sections. The staining methods depend in part on the fixation. In most cases I have 
obtained excellent pictures on staining with haematoxylin and counterstaining with cosine or picric- 
acid-fuchsine (van Giesson's). It is of interest to note, that the structureless organic ti.ssue, which 
intersects the skeleton in all directions, is coloured very intensely by the eosine and acid-fuchsine 
in the same way as the supporting lamellae of the zooids, whilst the picric acid does not affect it in 
van Giesson's staining method. — 

I cannot refrain from dwelling a moment here on the mineralogical composition of the skeleton. 
Pax has investigated the skeleton of Flabelbivi inconstans and found, that it consists of aragonite. 
He also brings together (1910 p. 70) the results of previous investigations in the same direction. Ac- 
cording to his summary calcite has been determined as skeleton in Coralliiim, his, Tii-bipora, Cysti- 
phylhtfii and Anabacia, whilst aragonite has been found in the following genera of Coelenterates : 
Heliopora, Monlipora, Rchinopora, Distichopora, Madrepora. Stylopora, Pocilopora, Millepora. Scriatopora, 
Goniastraea, Podobacea, Galaxea, Fungia, Dendrophyllia, Poritcs, Astroidcs, Hydnopliora. Sclcrohclin, 
Coeloria, Pterogyra, Merulina, Favia, Stylastcr and Trachypyllum. — At my request the assistant at the 
Geological Institute of the Polytechnic High School in Trondhjem, Dr. C. W. Carstens, has examined 
the skeletons of our four northern Stylasterids. Examination b>- means of Mei gen's reaction has 
shown, tliat the skeleton in all four is formed of aragonite. 

We here face one of the great problems of biology. There can be no doubt, that the power 
of animals to produce aragonite in the one or the other manner must stand in connection with their 
power to make use of the magnesium of the sea-water; according to the investigations of mineralogists 
namely all aragonite contains magnesium. But what makes the matter so puzzling is, that alongside 
the animals wliich have aragonite skeletons live some others, which like Corallium. Tubipora, Cysti- 
phyllnw and Anabacia form calcite skeletons. This shows that it cannot depend on a mere chance 
whether the animal builds its skeleton of aragonite or calcite. It seems more than doubtful that 
the crystalline system should be of an>- importance here. Physical characters might probably be 
found in aragonite, which for most of the marine animals make it biologically more profitable than 
calcite. Unfortunately the differences between aragonite and calcite in pln-sical regards are still 
so imperfectly known, that we arc unable to form any reasonal^le supposition as to wliat j^art their 
occurrence plays in the biology of the marine animal.s. 



STYLASTERIDAE 



The Stylasteridae of the North Atlantic. 

Pliobothrus Pourtales 

The colonies are branched fan-shaped, often with dichotoraonsly divided Inanches and branchlets. 
The gasteropores and dactylopores open irregularly over the surface of the colony and are not collected 
into cyclic systems. The dactylopores open out on the top of lower or higher tubular projections. 
The gasteropores are of varying depth, sometimes closed below by one or more tabulae; both the 
gasteropores and dactylopores sometimes open without distinct ending into the large, irregular, central 
longitudinal canals of the colony. The gasteropores and the dactylopores have no styles. 

With this diagnosis the genus agrees fairly closely with the Pliobothrus of Moseley (1881 p. 94). 
There are a few changes however which require further mention. Moseley included as a generic 
character in his diagnosis the absence of tentacles in the gasterozooid, in spite of the fact, that his 
own investigations indicated that Pliobofhrits tubidahis Pourtales has 5 — 6 tentacles on the gasterozooids. 
When we remember the great variation to which the number of tentacles is subject in other genera, 
where they have been studied, this character is of extremely problematic value as generic character. 
The same applies to the form of the polvps, which more than an\thing else is dependent on the state 
of contraction and preservation. So long as we are unable to demonstrate more constant peculiarities 
in the form of the polyps than hitherto, it has no great value even as specific characteristic. The 
number of the gonophores in the ampullae must also be referred to the specific characteristics and 
may even here be of subordinate importance. 

A close study of Pliobothnis symmefricus shows, that the pores of the zooids vary greatly in 
length and often stand in open communication with the large central canals which appear irregularh- 
in the branches. This blots out the boundaries between Pliobothrus and the genus Stcgatiopora recently 
described by Hickson and England (1905 p. 26). Open communications between the gasteropores 
and the dactylopores may also exceptionally be found in Pliobothrus sytiiiiirtricus. Steganopora must 
therefore be included under Pliobothrus. The species Steganopora spi?iosa Hickson and England, the 
only known species of this genus, stands very near to Pliobothrus tubulatus Pourtales and will possibly 
on closer examination prove to be identical with the latter. 

Pliobothrus symmetricus Pourtales. 

187 1 Pliobothrus syiinnctricus, Pourtales, Deep-Sea Corals p. 57, Plate IV, figs. 7 and 8. 

1874 — — , P. M. Duncan, Madreporaria .... "Porcupine" p. 336, Plate 49, fig. 7. 

1879 — — , Pourtales, Corals .... "Blake" p. 211. 

18S1 — - , Moseley, Stylasteridae "Challenger" pp. 48, 80 and 84, Plate VIII, fig. 2. 

The fan-shaped colonies are normally branched in one plane; sometimes a portion of the colony 
may develop to a new fan, which forms an angle with the primary plane. There is no distinct or 
prominent main stem. The gasteropores are evenly distributed throughout the colony, somewhat more 
numerous on the front than on the back. The dactylopores, which open out on low, broadly conical 



STYLASTERIDAE 



prominences, are mainly found on the front and lateral sides of the branches and are here irregularly 
arranged between the gasteropores. The gasteropores are sometimes provided with one or a few 
tabulae; both the gasteropores and dactylopores are sometimes in open communication with the ir- 
regular, large, central canals in the colony, exceptionally also with each other directly. The gastero- 
zooids have no tentacles. The dactylozooids, which are attached by a narrow base in the pore, have 
a central lumen. - The ampullae are deeply placed. The male gonophores are composite and are 
developed singly in the ampullae. - The surface of the colony is smooth, not reticulate. 

Colour (in alcohol): yellowish dirty gray. 

Occurrence: at Florida and in the Northern Atlantic in depths of 190— 700 m. 

Material: , , „ ^ 

"Ingolf" St. 55 63°33' N., i5°o2' W. depth 594 m. 5.9 . C. 

- - 57 63°35' - i3°02' - - 658 - 3.4". C. 

On the Ingolf Expedition some fragments and a complete colony of this peculiar species, which 
at first sight is all too readily regarded as a Bryozoon, were taken. The intact colony (PI. I, figs, i and 2) 
shows the marked tendency of the species to branch dichotomously. This characteristic is also clearly 
seen in Pourtales' and Duncan's drawings. How far this is more than a specific character we are 
unable at present to determine with certainty, as only a few quite small fragments have been found 
of the other species of the genus Pliobothrus. Pourtales' drawing of PUobothrus tubulatus (1871, 
PI. 4, fig. 9) suggests however, that we have here a .specific character, the fragment figured at any rate 
is not branched dichotomously. 

There is in general no verv marked main stem in PUobotlirns syninnctricus, nor do its branches 
show any regular difference in thickness. In this regard the intact colony of the "Ingolf differs from 
those described earlier; the unbranched, basal part of the colony may best be described as a kind of 
main stem, although its dimensions do not in reality differ obviously from those of the branches. 
The other, somewhat smaller fragments are not so distinctly and simply fan-shaped. Single branches 
show a tendency to new fan formations in i)lanes almost at right angles to the primary plane of the 
colony. As no other difference could be detected between the colonies, however, this must be 
considered as purely chance variations in the colonial form. — There is a sharply marked difference 
between the front and back of the colony. On the front the pores are evenly and densely distributed 
over the whole of the surface and here the dactylopores are present in large numbers; on the back, 
on the other hand, the dactylopores have practically disappeared and the number of gasteropores is 
also somewhat reduced. The difference becomes the more pronounced, the nearer we come to the base 
of the colony, the pores on the hind surface becoming more and more reduced both in number and 
size. In the above-mentioned, more irregularly branched fragments, all difference between the front 
and back disappears on the branches which emerge from the primary plane of the colony; the pores 
are evenly and densely distributed on the whole surface of these branches. 

Under a low magnification already (PI. I, fig. 3) we notice larger and smaller pores, which, 
however, are not arranged in rows or systems. The larger pores — gasteropores — have their opening 
plane at the level of the colony surface, whilst the small pores — dactylopores — are found on the 
top of small, conical protuberances. As mentioned above, the number of the dactylopores especially 



STYI.ASTBRIDAE 




Text-fig. A. Diagram showing 
the arched development of the 
pores in Pliobothnts symmetri- 
ciis during the growth of the 
colony. 



is reduced on the hind surface of the colony; what may be the cau.se of tliis our imperfect knowledge 
of the biological conditions of the Stylasteridac does not enable us to explain. 

If we grind down the branches to about the median longitudinal plane we are able to see the 
pores in the whole of their length (PI. Ill, figs. 19 and 20) and it becomes 
apparent that these have a txpical bend in their course, curving inwards 
towards the longitudinal axis of the branch and then downwards towards 
its base. The pores — especially the gasteropores — are of varying length; 
the terminal pores are, as a rule, quite short and much shorter than those 
we find further in on the branches. This indicates a terminal and centrifugal 
growth in the branch and gives us the key to the understanding of the bent 
course of the pores (Text-fig. A). The pores are first formed at or near the 
tip of the branch and approximately in its longitudinal direction; during the 
growth of the branch the jDore is gradually moved down on its cylindrical 
part. The plane of the opening of the pore lies at each place approximately 
at right angles to its longitudinal axis and the latter will therefore become 
curved during the growth of the branch, as will be seen from the ac- 
companying diagram. 

A few of the gasteropores open into large, irregular, longitudinal canals, which are formed 
secondarily in the central part of the branch; often however their base is formed of one or two tabulae. 
In their original form the gasteropores are cylindrical with a slightly expanded basal part in which 
the zooid is attached; but during growth the gasteropores often assume a more irregular appearance. 
The dactylopores also are of varying depth; they are cylindrical, more or less curved and have a 
slightly constricted opening region; the pore aperture itself, as mentioned, is situated on the top of a 
slightly prominent, almost wart-shaped protuberance. — The calcareous substance of the colony is 
penetrated longitudinally and transversely by fine canals in which the stolons lie. No regular arrange- 
ment could be noticed in these fine canals, neither in Pliobotlirus syt/unetncus nor in our other North 
Atlantic Stylasteridae. 

The connection of the pores and canal system in Pliobothrus syiiiiiictricus is of special interest, 
when we compare with the genus Steganopora established by Hickson and England (1905, p. 26). 
The open communication, which is not so very seldom observed between the pores and an irregular 
central canal system in Pliobothrus^ is said by Hickson and England to be a constant and always 
occurring character in Steganopora and here also results in an open and direct communication 
between the gasteropores and the dactylopores. Such a communication also occurs irregularly in Plio- 
bothrus symrnctriciis and we cannot consider this as a fundamental difference between this species and 
Steganopora spinosa^ as maintained by Hickson and England. In reality there is here only a gradual 
difference, which by no means entitles us to make a generic distinction and the last-mentioned species 
must therefore be referred to the genus Pliobothrus. 



Moseley (1881) has shown, that the structure of the zooids in Pliobothrus symmetrictis is very 
characteristic. The gasterozooid (Text-fig. B) has a fairly broad basal part, from the circumference of 




g STYLASTERIDAE 

which the Stolons emerge. Examination of serial sections seems to suggest, that the endoderm iu the 
basal part itself is strongly vacuolated; but this may also be due to the imperfect state of preserva- 
tion. The protoplasm is here strongly granulated and all indicates, that the albumen cells (cf. Schneider 
1902 p. 579) form the principal mass of the endoderm in the basal part of the polyp, whilst the 

nutriment cells are in majorit)' iu the endoderm of the free wall of the 

zooid. Apart from this localisation of the cell types the gasterozooid agrees 

/ in the whole of its structure with the Hydroid polyp, as is clearly shown by 

the figures (Text-fig. B, PL III, figs. 28 and 29). Whilst the large cnidocysts 

occur in fair numbers in the stolons, the small ones are concentrated in the 

walls of the zooids. In the gasterozooids (PI. Ill, fig. 29) the cnidocysts are 

Text-fig. B. The contracted accumulated densely in the ectoderjti near to the mouth of the polyp and 

gasterozooid of PUobothrus ^jj^jj-ely disappear further down on the polyp wall; in the dactylozooids they 

symmelrkns. ec = ectoderm, 

«/= endoderm, ;«=mouth, are more uniformly distributed iu the ectoderm in the whole length ot the 

.f = stolones, i^t^=theepi- ^^^.^ j^^^^. ^^^^^^^ however less numerous near its basis. — To judge from 

thel of the gasteropore, gp ' 

= mouth of the gastero- Moseley's drawing (1881 PI. VIII, fig. 2) the gasterozooid should have a wide, 

^ ' '' cruciform mouth iu PUobothrus syiiimctricus. The mouth of the polyp is 

closed ill all the specimens examined from the "Ingolf" Expedition and is neither larger nor shaped 

differently from tliat of the Hydroids generally. The cruciform appearance noted by Moseley is 

clearly due to chance, for the protruding parts of the endoderm in the numerous sections examined 

vary greatly in form, size and number. 

In their di.scnssion of the family characters of the Stylastcridac Hick son and England state 
(1905 p. 13): "The solid scalariform endoderm of the dactylozooids is another very distinctive feature 
of the grouj)". This does not hold good for PUobothrus symmetriais\ the dactylozooids have a distinct 
lumen in their centre, as shown in transverse sections (PI. IV, fig. 34). The authors cited maintain, 
that "the scalariform tissue is clearly a much more differentiated tissue", — naturally, under the tacit 
assumption, that the dactylozooid is a reduced polyp. This would suggest, therefore, that Moseley's 
view of PUobothrus as a primitive genus of the Stylastcridac is correct. 

There is one condition, however, which seems to point in the opposite direction; this is the 
male gonophores and their structure. Moseley indicated already, that their appearance differs from 
that found elsewhere in the Stylastcridac. But his drawing (1881 PI. VIII, fig. 3) is in so far misleading, 
as it gives the impression, that the difference only consists in a denser accumulation of very small, 
single gonophores. A series of sections through the male gonophores (PI. IV, figs. 40—42) shows ex- 
tremely aberrant features. Each ain])nlla contains a single, fairly large, globular gonophore, which is 
composed of a number of follicle-like portions (pseudofoUicles); the reproductive cells are in extremely 
different stages of development in the various pseudofoUicles of the gonophore. The spadix as a rule 
is slightly branched between the pseudofoUicles and sometimes we find, that slender connecting bridges 
lead from the stolons of the ampullar wall over to other parts of the gonophore wall than those where 
its spadix connects with the stolons of the colony. — Hickson (1891) has demonstrated the forma- 
tion of a "seminal duct" in Stylastcridac where the male gonophores are of primitive structure. Such 
a formation can certaiul)- not be found in PUobothrus symmetricus. The apex of the compound goiio- 



STYLASTERIDAE 



phore is prolonged (PI. IV, fig. 42) but seems never to reach the surface of the colony. To 
judge from serial sections it opens out into one of the surrounding stolon canals of the calcareous 
skeleton at the side of and not in the stolon itself. The available material however is not sufficiently 
well-preserved to enable these conditions to be closely studied, nor does it give any clear picture of 
the structure or development of the opening of the gonophore. 

It would be of great interest to clear up the origin and development of these compound gono- 
phores. Probablv we have here a secondary coalescence of the whole gonophore complex which we 
find collected into the single ampulla in most of the other Stylasferidae. The branched spadix and 
the variating stage of development of the reproductive cells in the single pseudofoUicles point in this 
direction. Investigation of the Stylaster species shows, that the male gonophores in an ampulla are in very 
different stages of development and thus function over a long period; the successive maturation, which 
obvioush- must be of great importance for the species, is thus retained in Pliobotlirus syinntctriciis after 
the gonophores have become fused into a single complex. Unfortunately the material has not per- 
mitted any close study of the development of the gonophore in the present species. — I was unable 
to find other developmental stages of the female gonophores than those already known from the 
work of Moseley. Thus nothing was found which differed from his description. — 

Pliobothriis symmetricus was first described by Pour tales (1871) from the Florida reefs, 
where it seems to be common between 180 and 300 m. in depth. The species has only once been 
met with in the Northern Atlantic, where P. M. Duncan (1874) mentions it from the cold area of 
the Faeroe Channel. 

Stylaster Gray."^ 

The usually fan-shaped colonies have the zooids collected into closed cyclosystems, which show 
no trace of opercula. Both the gasteropores and the dactylopores are provided with stjles; the dactylo- 
styles however may be rudimentary. 

On the basis of this diagnosis we must also include the genus Allopora Ehrenberg in Stylasta: 
Hickson and England (1905 p. 6) rightly point out how .small and doubtful the characters are, 
which are said to distinguish the two genera. In reality there are quite even transitions between the 
genera. None have shown this more clearly than Hickson and England, who following the 
proposal of Studer group the species into four divi.sions: "A. Cyclosystems on lateral sides of branches 
only; B. Cyclosystems on lateral sides of branches and a few on the surfaces; C. Cyclosystems evenly 
distributed over the surfaces of the branches, and D. Cyclosystems on the anterior surface of the 
branches only." The first two groups stand extremely near to each other and should be embraced 
within one main group or subgenus Eustylastcr\ the last group has just the arrangement of the 
cyclosystems which is characteristic of Allopora; species like Stylaster diver gens Marenzeller and Allo- 
pora rosacea Greeff obviously occupy intermediate positions between our northern Allopora species with 
its hardly prominent cyclosystems and those Stylaster species which have very prominent, almost 
stalked cyclosystems. For group D. the old generic name Allopora should be retained. 

The genus Stylaster is represented in the Northern Atlantic by three species, which have been 
confounded several times. When the ampullae are strongly developed the colonies in our Fm- 



8 



STYLASTERIDAE 



stylaster species may sometimes become so blown up and deformed that they may easily enough be 
confused with the Allopora species. To facilitate the determination in difficult cases I give in the 
following table their distinctive features. 



gevimascens 



norvegica 



Cyclosystems 



Gasterostyles 



.'ViiipuUae (9) 



with 12— 20, normally 14— iSdactylo- 

pores. Wall of gasteropore deeply 

incised towards the dactylopores. 

conical, twice as high as broad. 

near thesurfaceand projecting like a 
hemisphere; equipped with blunt spines. 



with 8 — 16, normally g — 11 dactylo- 
pores. Wall of gasteropore slightly 
incised towards the dactylopores. 

almost globular with same breadth 
as height. 

near thesurfaceand projecting like a 
hemisphere; without .spines. 



with 5—9, normally 6 — 7 dactylo- 
pores. Wall of gasteropore sUghtly 
incised towards the dactylopores. 

almost globular with same 
breadth as height. 

deeply embedded, scarcely seen 
externally on the colony. 



Subgenus Eustylaster nov. 

Stylaster gemmascens (Esper) Milne-Edwards et Haime. 
1768 Madrepora virgmea, Gunnerus, Om nogle nor.ske Coraller p. 56, Tab. VIII, figs. 2—4. 
nee 1758 Madrepora virginea, Linne, Systema naturae ed. X, vol. I, p. 798. 
? 1797 Madrepora gemmascens, Esper, Fortsetzungen der Pflanzenthiere, T. I, p. 60, Tab. 55. 
1857 Stylaster gemmascens, Milne-Edwards, Histoire naturelle des Coralliaires p. 130"). 
1873 - - 

?i874 - - 

1879 - - 

1881 — 

1882 — — 
1910 — — 
1912 — — 
1912 — — 



- — , G. O. Sars, DyreHvet paa vore Havbanker p. 45. 

- — , pars, P. M. Duncan, Madreporaria .... "Porcupine" p. 332. 

- — , Storm, Bidrag til Kundskab om Trondhjemsfjordens Fauna p. 24. 

— , Moseley, Stylasteridae "Challenger" p. 86. 

- — , vStorm, Bidrag til Kundskab om Trondhjemsfjordens Fauna IV, p. 25. 

— , J- A. Thomson, Note on a Hydrocoralline from Rockall p. 61. 

— , Nordgaard, Faunistiske og biologiske iagttagelser p. 7. 

- — , Arndt, Zoologische Ergebnisse, I, p. 122. 

The fan-shaped colonies have as a rule a concave front surface and show a distinct difference 
between stem, main branches and small branches. The cyclosystems are placed laterally and alternately 
on the outermost small branches and their main axis forms almost without exception a pointed angle 
of less than 45° with the axis of the branch; they are oval, except those just at the tip of the branch 
which may be circular, and show from 12 to 20, normally however 14—18 quite separate dactylopores, 
each provided with a rudimentary dactylostyle. The wall of the gasteropore shows deep incisions to- 
wards the dactylopores. The gasterostyle is conical, twice as high as broad. The gasterozooid 
has 4 quite small tentacles. — The female ampullae project like hemispheres above the surface of 
the colony and when fully developed are equipped with i -7, generally 2-4 small, blunt .spines. The 
surface of the colony is smooth and indistinctly reticulated. 

Colour: white or faintly rose-red with darker yellowish red gasterozooids. 

Occurrence: west coast of Norway, Denmark Strait in 50-560 m. depth, Rockall. (Indian Ocean?) 

•) This work contains a detailed list of the older synonymy. 



STVLASTKRIDAK 



Material: 

"Ingolf" St. 15 66°i8'N. 2.5°59"W. 620 m. -^o.75° C. 

Hjeltefjord ca. 150 111. 

Gidsko (Sondmore) ? 

Sondiiiore ? 

Trondhjem Fjord 50—400 m. 6.5 — 8.5° C. 



West coast of Norway 



The form and appearance of the colonies are snbject to snch great variations in Stylaster 
gcinmasccns, that we nia>' often be in doubt as to whether one and the same species is before us. The 
available material was very large, especially from the Trondhjem Fjord, where the species is fairly common 
and more luxuriantly developed than from any other localit\- hitherto known; further, I was able to examine 
a number of colonies from the west coast of Norway and lastly a couple of small fragments from 
"Ingolf" St. 15. Examination of this very large material shows the relationship of all the many 
different kinds of variants, partly owing to series of chain-forming variants, partly on account of 
apparently quite different growth-types being present in different branches of single colonies. Hicks on 
in several of his works has divided up some of the species into a series of different "facies". As the 
most illustrating examples I may mention his treatment of Stylaster eximiits Duchassaing et Michelotti 
(1905) and Errina nova-zclandiac Hickson (1912). The deeper meaning of these "facies" is not apparent from 
his method of treatment; the}- seem only to illustrate the varying growth modifications of the species; nor 
do we obtain any information as to the biological conditions under which they appear. In dealing with 
the present species, therefore, I discard the subdivision into "facies", which only serves to give the misleading 
impression that the sj^ecies is divided into distinctly separated growth forms or types. 

There is always a distinct difference present between the front and hind surfaces of the colony 
in Stylaster gemmascens and the more or less composite, fan-shaped colony is almost always bent some- 
what inwards, so that the front surface becomes more or less concave. To give any explanation of 
the biological significance of these structural features cannot be done with certainty at present, least 
of all for our northern species, which onh- live in great depths. A conclusion by analogy from tropical 
species is excluded, since, as Hickson and England (1905 p. 4) point out, we lack all knowledge of 
the biology of these animals. — There is a gradual increase in thickness from the outermost small 
branches and inwards towards the thick main branches and main stem; the last are almost entirely 
free of cyclosystems. The small branches may sometimes show coalescences, but this is seldom. 

On the outermost, fine branches we see how the cyclosystems arise alternately on the lateral 
sides of the branch; this is the primary condition in the species. The larger cyclosystems however 
are not restricted to the lateral part of the branch; they also extend far in over the front surface of 
this, as can be seen regularly a few millimetres inside the tip of the branch. The increase in thickness 
of the branch proceeds most rapidly on the hind surface; in this we may have one of the causes of 
the colony's tendency to bend in towards the front surface. It has the further effect, that the cyclo- 
systems are secondarily moved more and more forwards towards the front of the branches, the nearer 
we come to their origin; at the same time a few irregularly situated, new cyclosystems arise between 
the old. Here and there we also find, that cyclosystems appear quite singly on the back of the colony 
but their number here is always very small. - - 

riie Ingolf-Expedition. V. 5. 2 



jQ STYLASTBRIDAE 



When the material available only consists of some few fragments of Stylaster gnnmasccus, we 
may often be inclined to divide it up into several species, as already mentioned. Some pieces 
(PI. I figs. 5—6) show a regular aspect with uniformly constructed branches; others on the other hand 
(PI. I, figs. 4 and 7) are irregular in their mode of branching and in the arrangement of the cyclosystems. 
A larger material soon shows however, that there is no justification in creating subspecies on the 
basis of these variations. Often the appearance of the ampullae may alter the regular structure of the 
colony, though not quite so much as in the following species, with which it can easily be confounded. 
The most reliable mark of distinction between the two species is found in their cyclosystems and 
gasterostyles. But the female ampullae also afford good characters; in Stylaster gemmasccns they are 
equipped with a varying number of conical, blunt spines; normally we find 3 or 4 of these on the 
ampulla, more seldom 2 or i; often the number may also be. larger and once 7 spines were foinid on 
a single ampulla. When the ampullae occur in larger number, these small spines appear in quantities 
between the cyclocystems and make the boundaries and arrangement of these indistinct to the naked 
eye (PL I fig. 7). Closer examination however shows that the cyclocystems are comparatively little 
affected by the ampullae. 

The cyclosystems appear as small, oval, stellate elevations except at the very tip of the branches, 
where they are still circular in circumference. Even the tops of the septa-like separating walls between 
the dactylopores project somewhat strongly above the surface of the colony. The number of the dac- 
tylopores in the cyclosystems varies from 12 to 20; in general there are from 14 to 18 dactylopores 
round a gasteropore. The wall of the gasteropore shows a deep incision towards the dactylopore. 
Any fusion of the dactylopores which lie side by side could not be detected, as is often the case in 
some tropical species. — Carefully prepared longitudinal sections made by grinding readily show the 
gasterostyle (PL III fig. 21); in Stylaster gem mas c ens it is pointed, conical and almost twice as high as 
broad. A thin section (PI. Ill fig. 24) shows clearly its lattice-work structure. The dactylostyles are reduced 
to faint, irregular elevations on the outer wall of the pores; they are very difficult to observe. — 
Thin sections of the stem and main branches show very distinctly, that the growth here as in our other 
northern Stylaster species proceeds centrifugally and periodically; but it still remains to discover, what 
influences in the sea produce this periodic growth in the colonies. 

Tlie gasterozooid has the same structure as the hjdroid polyp, when we exclude the secondarily 
formed gasterostyle (Text-fig. C, PL III fig. 25). Partly near to and partly somewhat below the opening 
of the mouth we find four quite small, almost rudimentary tentacles. The small cnidocysts of the 
polyp are gathered in these tentacles, though witliout leading to the formation of a typical, thickened, 
distal part such as is found on the capitate tentacles of the Corynidac\ their structure agrees full\- with 
the thread-like tentacles we find in tlic athecate Hydroids. Tlie ectoderm of the gasterozooid is nor- 
mally destitute of stinging cells otherwise. The cell boundaries in the ectoderm are very difficult to 
make out; the whole structure here agrees with that of the Hydroids. Often we can observe out- 
runners which connect the ectoderm of the polyp wall with the epithelium of the gasteropore wall; 
these resemble the irregular outrunners, which are often found in the thecaphore Hydroids and which 
here connect the ectoderm of the h)dranth with the hydrotheca outside the true, basal line of attach 



STYLASTERIDAE jj 



■'t:J 



i 



ment. — The gasteiozooid is provided with a strongly developed, supporting lamella. The endoderm 
cells are high and show the same cell types that are nsnally fonnd in the lower Coelenterata; the en- 
doderm continnes on to the gasterostyle and forms its epithelial covering. Distinct cell bonndaries 
can in general not be observed in the endoderm of the gasterostyle; the grannlated 
strncture shows, that the albnmen cells are decidedly in majority here, whilst 
Schneider's "Nahrzellen" (1902 p. 579) compose the main mass of the cells in 
the endoderm of the free gasterozooid wall. 

A transverse section of the basal part of the gasterozooid gi\es an extremely 
characteristic picture (Pi. IV fig. 32). The tissues collect into separate colunuis 
which gradually become smaller in diameter and pass over into the stolons. No 
lumen could be detected in these columns until the)- change over into the typical 
stolons. Nor do they show any sign of differentiation into ectoderm and en- 
doderm like the stolons. The number of columns does not seem to be constant. 



The dactylozooids (PI. IV fig. 33) have a very thick and muscular sup- Text-fig. C. Diagram- 

,. , ,, , , , , r • 1 y .- uiatic median section 

portmg lamella and show a more marked power of expansion and contraction ^, , ^, , , 
^ '=' ' ^ mrougli the cyclosystem 

than the gasterozooid. The thick ectoderm of the free wall of the dactylozooid of styiasu-r (Eustyiaster) 

is densely beset with cnidocvsts, but the zooid is not capitate. The endoderm is ? \ . ji 

^ - ' '^ les are not represented 

scalariform and compact and thus the dactylozooid has no central lumen. The in this section. (/=dac- 

11 ■ 11-1 1111 • 1 11 1 ■ tvlozooid, f' = free por- 

eudoderm is on all sides surrounded by the supporting lamella and is not con- : of th b d ' ■ U f 

nected with the endoderm of the stolons. The nutrition of the dactylozooid from the gasterozooid, gs = 

the stolons must therefore take place through its ectodermal wall. — 

In spite of the very large material available for investigation I did not succeed in finding 
the male colonies and determine their number of gonophores in the ampullae. Nor were young stages 
of the female gonophores fonnd in the numerous sections. The fully developed female gonophores 
(PL V figs. 46 and 49) have a complicated spadix. From a narrow base, where the main stolon enters 
into the ampullae, the spadix spreads out semispherically; it is formed by numerous, fine, endodermal 
blind sacs, the narrow and irregular lumens of which radiate out like the rays of a star from the centre of 
the base of the gonophore. As the single blind sacs as a rule have a twisted course and not seldom 
branch, the whole picture thus seems very complicated at first sight. The ripe ovum rests on the spadix 
like one hemisphere on another and the spherical gonophore, which occupies the ampulla, is surrounded 
by a thin endodermal layer. The colonies are not hermaphrodite and it is a puzzle even how fertiliza- 
tion takes place in these animals with their closed ampullae. — As the ovum gradually develops to a 
planula larva and grows in size, the spadix atrophies, its large cell material being probably used for 
the nourishment of the ovum. When the spadix is more reduced (PI. V fig. 50) its structure be- 
comes more distinct. — Other stolons of the wall of the ampulla may also secondarily come into 
connection with the gonophore and thus increase the amount of nourishment during the embryonal 
development. 

It has long been an open question whether the larva ruptures the roof of the ampulla when 
it escapes. A series of sections through a number of large, empty ampullae points in an opposite 
direction; in .spite of the fact, that the larva must just have escaped from the ampullae, their roof is 



12 STYLASTERIDAE 



quite intact. It is probable indeed, that a fairly small opening is simply formed in the roof of the 
ampulla, through which the larva escapes. This opening is at once closed again and the ampulla 
persists for some time as a large empty space after the larva has escaped. The further fate of the 
ampulla has not been observed. 

The synonymy of the species offers several difficulties. It is exceedingly doubtful, if it really 
was this species which Esper (1797 p. 60) described under the name of Aladrepora gemmasccns and 
the question cannot be settled from the literature. The reason for nevertheless retaining the specific 
name gemmascens here i.s, that our commonest northern Stylastc>\ wherever it is mentioned in the 
literature, appears under this name. Esper's specimens came from the Indian Ocean but no one 
has later found the species there. — The first quite certain and detailed description of the species is 
to be found in a treatise of Gunnerus (1768 p. 56), who erroiieously identified it with Linne's Madrc- 
pora virginea; his drawings are the best which have ever been given of the species and the identification 
is all the more certain because his specimens are still preserved in the Zoological Museum of Trondhjem. 
One of them is reproduced in fig. 4 of PI. I. Gunnerus examined several colonies of this species from 
the we.st coast of Norway, but his work has been pas.sed over by later investigators and thus Esper 
has erroneously been taken as the first describer. We thus find, that Milne-Edwards (1857) was still 
unacquainted with the fact, that Stylaster gemmascens lives in northern waters. It was reserved for 
G. O. Sars (1872 p. 45) to point out its existence on the Norwegian coasts and he was the first to 
refer the northern colonies to Esper's .species. In this he is followed by P. M. Duncan, who how- 
ever in his work on the material of the "Porcupine" (1S74 p. 332) confounds it with Stylaster roseus and 
Stylaster {Allopora) Jiorvegictis; on the whole, to judge from his drawings it is extremely doubtful if 
Duncan has had any specimens at all of Stylaster gemmascens. Storm (1879 and 1881) found the 
species again in the Trondhjem Fjord and points out that it is fairly frequent in its occurrence there. 
Lastly, we find Stylaster gemmascens mentioned from Rockall; through the kindness of Prof. J. A. 
Thomson I have had the opportunity of examining his specimens, which are typical individuals of 
the northern .species; it is the only certain instance of its occurrence south of the submarine ridge between 
Scotland —Iceland and Greenland. Excluding Esper's locality the .species has not been found outside 
the North Atlantic and even there it lives within a fairly restricted area. 



Stylaster roseus (Palla.s) Gray 
1766 Madrepora rosea, Pallas, Elenchns Zoophytorum p. 312. 

1857 Stylaster roscits, Milne-Edwards, Histoire Naturelle des Coralliaires T. II, p. 130'. 
1871 - erubescens, Pourtales, Deep-Sea Corals p. 34, PI. IV figs. 10 and 11. 
?i87i — roseus, Pourtales, I.e. p. 83. 
1874 — gemmascens pars, P. M. Duncan, Madreporaria . . . "Porcupine" p. 332, PI. 49, figs. 13-15. 

1877 — rose2is, Liudstrom, Contributions to the Actinology of the Atlantic Ocean p. 15. 

1878 — rrubescens, Pourtales, Corals . . . "Blake" p. 210. 

1881 — roseus -\- S. erudesccns, Moseley, Sl\-lasteridae, "Challenger" pp. 86 and 87. 
') This work contains a detailed list of the older synonymy. 



STVLASTERIDAK i^ 



The fan-shaped colonics are in general branched in one plane and not recnrved; they display 
a marked difference between small branches, main branches and stem. The cyclosystems are placed 
laterally and alternately on the small branches; their main axis forms an angle of 45"" or more with 
the longitndinal axis of the branch. Tlie cyclosystems are circular except on the thick main branches, 
where they have a more oval form. The cyclosystem shows from 8 to 17, in general 9— 11 quite 
separate dactylopores, each provided with an almost rudimentary dactylostyle. The wall of the 
gasteropore has quite a small incision towards the dactjdopores. The gasterostyle is almost spherical 
with the same height as breadth. The gasterozooid has four very small tentacles. — The male am- 
pullae generally contain 4 10 6 gonophores and are scarcely seen on the surface of the colony. The female 
ampullae appear like hemispheres on the surface of the colony; they are smooth, without spine.s. 
The surface of the colony is .smooth and faintly reticulate. 

Colour: rose with lighter stem and main branches. 

Occurrence: Atlantic Ocean in depths from 230 to 1400 m. 

Material : 

"Ingolf" St. 7 63°i3'N., i5°4i'W. 1128 m. 

- 15 66°i8' - 25°59' - 

- - 17 62°49' - 26°55' - 

- 52 63°57' - i3°32' - 

— - 94 64=56' - 36° 19' - 
"Thor" 1904 65°5o' - 26°53' - 
East Greenland Expedition. Off Angmagsalik 

At first glance Sfylaster rosciis is confusingly like the preceding species; it may especially be 
easily confounded with such colonies of the latter as are represented in figs. 5 and 6 of PI. I. Closer 
examination however shows that there are great and constant differences between the colonies, so that 
they must be taken as representatives of different species. The first mark of distinction apparent on com- 
paring larger colonies is the form of colony itself. In Stylasfrr roseiis there is a greater difference 
between the main branches and the small branchlets than in the preceding species and the colony is 
more robust; in addition, the branching of the colon>- in Sfylaster roseiis normally proceeds in a single 
plane and it seldom shows a slight tendency to curve inwards towards the front surface. When the 
colonies are in full process of reproduction they are often so swollen also in the outermost 
small branches (PI. II, fig. 11) that there is danger of confusing the species with Stylastcr {Allopora) 
norvegica. The position of the cyclosystems in relation to each other on the outermost small branches 
however shows that the species here dealt with belongs to the subgenus Eiisiylasfer. The main axis 
of a cyclosystem is at right angles to the axes in the inner-lying and the succeeding cyclosystems and 
this is more obvioirs than in Sfylaster geiiiviasceiis^ where the cyclosystems owing to the smaller angle with 
the branch axis do not give the small branches such a distinct zigzag form as in Stylastcr rosetis. In 
addition the number of the dactylopores is on the whole less in Stylastcr roscus, their number varying 
between 8 and 17 but in general lying abont g to 11. Further, the communication of the dactylopores 
with the central gasteropore takes place through a smaller incision in the gasteropore wall than in 
Stylastcr gciiunasccns. 



128m. 


4-5° C. 


620 - 


-0.75° - 


400 - 


34° - 


789 - 


7.87° - 


204 - 


4.1° - 


392 - 


? 


263 - 


? 



J. STYLASTERIDAE 



The most decisive and constant characters however are found in the condition of the gastero- 
styles and ampullae. Whilst the gasterostyle in the preceding species was conical and twice as high 
as broad, in Stylastcr roseus it is almost transformed to a spherical lattice-work (PL III, fig. 22), which 
rests with a broad base on the bottom of the gasteropore. In fertile colonies the female gonophores 
especially project like hemispheres above the surface of the colony; whilst the female gonophores in 
the preceding species were equipped with spines, in the present species they are quite smooth. These 
are important differences, which compel us to consider the colonies as representing quite different species. 

Examinition of the structure of the tissues in Stylaster roscns reveals such small and unessential 
differences from Stylastcr gemmascens^ that we can only ascribe them to the bad preservation of the 
specimens of the present species. It is only represented in the material by dried fragments and 
colonies, which have been placed directly in 70% alcohol. The only difference which might possibly prove 
to have some importance is, that the large stinging cells, which are extremely seldom in Stylastcr 
gemmascens and Stylastcr [Allopora) norvegiciis^ are fairly numerous in the stolons of Stylastcr roscus\ 
they are not found here either in the zooids. 

Most of the colonies are fertile. There is nothing to indicate that they are hermaphrodite and 
the largest specimens, which come from the waters off Angmagsalik (Greenland), are male. The condi- 
tion of preservation of the material did not permit any exhaustive examination of the gonophores. 
I shall therefore only refer here to some few features, which have some interest when compared 
with the few and scattered observations hitherto reported regarding the gonophores of the Stylastcridac. — . 
On young developmental stages of the male gonophores (PI. IV fig. 36) we see, that the gonophore 
has a well-developed central spadix, which however does not reach the apex of the gonophore 
No trace could be found of an endodermal cell layer under the ectoderm, which according to Hickson 
(1891 p. 392) surrounds the spermarium of the gonophore in the Stylastcridac. Nor did I succeed in 
finding indications of such a cell layer in the later developmental stages. — When the sexual cells ap- 
proach maturity we still find a distinct spadix (PI. IV fig. 39) which extends into the spermarium to- 
wards the centre of the gonophore. During the transformation of the spermatocytes to spermatozoa 
the spadix atrophies and disappears in gonophores with fully developed spermatozoa. 

During the last transformation we should expect to find the development of the seminal duct, 
wliich according to Hickson is characteristic of the Stylastcridae. Fig. 43 of PI. V shows the condition 
in Stylaster roseus at a spot where the seminal duct should be expected; the picture is of a gono- 
phore with the spermatozoa almost fully formed. A slight thickening of the ectodermal epithelium 
can be detected both in the gonophore and on the adjacent part of the roof of the ampulla; but a 
comparison with other gonophores indicates that this is merely a chance. Even at this place, where 
tlic spermatozoa would very soon escape, we find no trace of the formation of a seminal duct. 
The apex of the gonophore points towards a neighbouring stolon canal and at other places also the 
conditions suggest, that the gonophores of the ampulla empty their ripe sex cells into adjoining stolon 
canals and not directly out through the roof of the ampulla. The conditions seen cannot be explained 
by the state of preservation, for they are the same in all the cases, where the course of the cell layers 
can be determined with certaintv. 



STYLASTERIDAE j. 



The female gonophore in its fundaiiiental features is constructed as iu Stylastcr gemmasceiis. 
But its spadix is simpler in structure (PI. V figs. 47 and 48); it is bowl-shaped. Whilst the spadix 
in Stylastcr gciiunascois develops blind sacs iu the direction towards the central parts of the ."ono- 
phore, all the blind sacs in Stylastcr roscits lie along the j)criphcry of the gonophore. The structure 
may here be said to be more primitive than iu Stylastcr gciiimasccns. 

The s}'nonyniy of the species is not easily determined with certainty from the literature. No 
differences between the available colonies and the old descriptions of Stylastcr roseus can be found. 
As the species is the commonest Stylasterid iu the Atlantic north of the equator, it is probabh- the 
same form that served as a basis for Pallas' description of Madrepora rosca\ the name also agrees with 
the colour as noted by the collectors of the present material. The only disagreement to be noticed 
between these colonies and Milne-Edwards' description (1857 p. 130) is, that the small branches 
seldom show coalescences; but this character is of little importance and can scarcely be con.sidered 
sufficient as a specific distinction. Pourtales (1871 p. 34) under the name of Stylastcr criibcscens 
describes a species from the deej^er lajers at Florida; his excellent figures show at once, that it can- 
not be specificalh' distinct from the North Atlantic Stylastcr roseus; on the other hand, it is exceedingly 
doubtful if it is this species which he (1. c. p. 83) with doubt refers to Pallas' species as Stylastcr 
roscits. P. j\I. Duncan (1874 PI. 49 figs. 13 — 15) figures the species from the Faeroe Channel, but refers 
it erroneously to Stylastcr gciiii/iasLcns. Stylastcr rosc/is is couunon in the northern Atlantic south of 
the submarine ridse between Scotland— Iceland and Greenland. 



Subgenus Allopora (Ehrenberg) 
Stylaster norvegicus (Gunner us) 

1768 Millcpora uorvcgica., Gunnerus, Om nogle nor.ske Coraller p. 64, Tab. II figs. 20 — 22. 

1873 Allopora norvcgtca., G. O. Sars, Dyrelivet paa vore Havbanker p. 45. 

1874 Stylastcr gcmi/iascciis pars, P. M. Duncan, Madreporaria . . . "Porcupine" p. 332, PI. 49 figs, i — 3. 

1881 Allopora oc2di)ia^ Moseley, Stylasteridae, "Challenger" jx 85. 

1882 — norvegica, Storm, Bidrag til Kundskab om Trondhjemsfjordens Fauna, IV, p. 26. 

1888 — ocidina -f- A. norvcgica., Hicksou, On the maturation of the ovum and Development of 
Allopora p. 595. 

The fan-shaped colonies are generally branched in one plane; they are not recurved and show 
no distinct divi.sion into stem and branches. The cyclosystems are arranged irregularly; the}- are most 
numerous on the front surface of the colony. They are circular or more rarely somewhat oval and 
have from 5 to 9, in general 6—7 quite separate dactylopores, each with a faintly developed dactylo- 
style. By means of a shallow incision the gasteropore stands in communication with the dactylopore. 
The gasterostyle is approximately spherical, of the same height as breadth. The gasterozooid lias 
from 5 to 7, in most cases 6 quite small tentacles. — The ampullae are deeply imbedded and are hardly 
seen on the surface of the colony. The male ampullae contain iu general 3, seldom 2 or 4 gonophores. 
The surface of the colony is smooth, not reticulated. 



i6 



STYLASTERIDAE 



620 111. 


-0.75° c. 


1400 - 


3-4° - 


790 - 


7.87° - 


594 - 


5-9° - 


392 - 


■? 


? 


? 


? 


? 


-400 - 


6.5-7-5° C. 



Colour: white or faintly rose with strongly yellowish red gasterozooids. 

Occurrence: North Atlantic and west coast of Norway at depths from 100 to 1400m. 

Material : 

•'lugolf St. 15 66°i8' N., 25°59' W. 

— - 17 62°49' - 26°55' - 

— - 52 63°57' - i3°32' - 

— - 55 63°33' - i5°02' - 
"Thor" 1904 65^50' - 26°53' - 

Hardauger Fjord 
(G. O. Sars leg. 187 1) Storeggen (at Aalesund) 
Trondhjein Fjord . i 

Stylaster norvegicus is of coarser make than the preceding species (PI. II figs. 12—15) and shows 
no distinct main stem. Even the outermost tips of the branches may often be very thick (PI. II fig. 15) 
and the cyclosystems show no regular arrangement as in our Eustylastcr species. Nevertheless super- 
ficial observation may easily confuse the species with colonies of the preceding species which are de- 
formed by the numerous ampullae (cf. PI. II, fig. ii). ~ The branches in Stylaster norvegicus are often 
flattened in the transverse plane of the colony. There is a marked difference between the front and 
back, the number of cyclosystems being very greatly reduced on the back of the colony (PI. II 
figs. 13 and 14). 

The cyclosystems are very regular in their formation in Stylaster norvegicus. They are almost 
circular and surrounded by a slightly raised ridge, which continues out into the septa between the 
dactylopores. As the ampullae are very deeply immersed, their development causes no disturbance of 
the regular form of the cyclosystems. In general there are 6 or 7, more rarely 8 quite separate dactylo- 
pores round the open and deep gasteropore. The wall of the gasteropore shows an incision not specially 
deep towards the dactylopore. — The short and broad gasterostyle is very characteristic; it is 
approximately spherical and has almost the same breadth as height (PI. II fig. 23). The dactylostyles are 
a little more prominent than in the two previous species, but they are also rather difficult to ob- 
serve in Stylaster norvegicus. 

The ampullae are deeply imbedded in the branches and in general cannot be seen externally 
on the colony; but branches with ampullae are on the whole thicker than sterile branches. — The 
growth of tlie colony proceeds after the same type as in the Stylaster species already dealt with; 
the concentric layers, which indicate a periodic growth in the colony, are also distinct here on thin 
transverse sections of branches of the colony and are also readily seen in transverse series of sections 
of branches which are freed from their calcareous substance. 

Whilst in tlie two preceding species we constantly find four tentacles on the gasterozooids 
the number varies in Stylaster norvegicus. As a rule the gasterozooid has 6 quite small tentacles, but 
sometimes their number is reduced to 5 or increased to 7. The tentacles (Text-fig. D, PI. Ill fig.s. 27 and 31) 
are also very small here; we might be inclined to call them rudimentary. The\- are also here the seat 
of the small cnidocysts, which the gasterozooid is on the whole provided with. There is no reason 



STYLASTERIDAE 



17 













r 




91 










gs 


gw 




p 




















^ 



1, 



dian section through the cyclo- 
systein of Stylaster (Allopora) nor- 
vegkus. d = dactylozooid, gt ^^ 
tentacle of the gasterozooid, gs 
= gasterostyle, gw = free part 
of tlie body-wall of the gastero- 
zooid. 



whatever here or anywhere else to call the tentacles capitate; the\- are formed quite like the thread- 
like tentacles in the athecate hydroids. — P'urther, the gasterozooid shows in its finer structure no 
difference from what has been described in Sfyl'isfrr (Eitsfylas/rr) gn/unas- 
cens. In the present species it is also broken np at the base into a circle 
of columns, the number of which seems mostlv to be about 6. — The 
structure of the dactylozooid also agrees with that in the other northern 
species of Stylasfrr; but the dact\lozooids are somewhat larger in Sfylasfrr 
norvrgicus than in the previous species. The large cnidocysts are found 
in extremely small numbers in the stolons. 

Whilst the preceding species was only represented by specimens Xgxt-fig. D. Diagrammatic me 
not very well-preserved, the opportunity was taken to obtain fresh material 
of Stylaster norvegiciis from the Trondhjem Fjord, in the outer part of 
which the species is fairly common in suitable localities. Both male and 
female colonies could be examined and even if most of the questions 
concerning the development of the gonophores must still remain un- 
answered, yet the investigation contributes a good deal to the understanding of the nature of the 
gonophore in Stylaster. 

The sexual cells are alread)- present in the youngest developmental stage of the male gono- 
phore which was found (PL IV fig. 35) so that their origin cannot be settled. The gono- 
phore shows clearly, that Hickson (1891 p. 384) was wrong in maintaining, that "the sperniarium is 
covered by a double sheath of very thin etcoderm and endoderm". Neither at this stage or later can 
anything be seen in the numerous gonophores examined (PL IV, fig. 37), which could be taken for an 
endodermal layer between the ectoderm and the generative cells. — Hickson (I.e. p. 390) maintains 
as a typical difference between the gonophores in Allopora and Disticliopora that the latter genus has 
no spadix, whilst Allopora has a strongly developed spadix. In Stylaster [Allopora) norvegiciis the 
spadix is strongly developed in the young gonophores but atrophies during the transformation of the 
sperm cells (PI. IV fig. 38) and lastly disappears entirely in the mature gonophore as is the case also 
in Stylaster roscus. 

The present species forms in part the basis for Hickson's studies on the seminal duct. 
Unfortunately I did not succeed in finding all the developmental stages of it and it is remarkable 
that it is not always to be found in almost or quite ripe gonophores in spite of the fact, that the preserva- 
tion of the material is excellent. It seems doubtful, if under all conditions it conies to development 
even in all gonophores within the same colony; its importance therefore must be reduced in the 
general considerations on the group. — The youngest developmental stage found (PL V fig. 44) appears 
as a collection of somewhat higher and lighter-coloured cells at the apex of the gonophore. The rudi- 
ment is distinctly double, for under the thickened ectoderm cells there is a collection of inner cells (I), which 
have a characteristic, almost fibrillar protoplasmic structure; these fairly large and light-coloured cells 
are separated from the outer ectodermal layer by a very fine lamella. At a more advanced stage, 
when the seminal duct is almost fully formed (PL V fig. 45) the inner cells push the thin lamella in 
front of them into a conical point, which is surrounded by the more deformed ectodermal cells. The 

The Iiigolf-Ksiif Jitinn. V. ; . ^ 



l8 STYLASTERIDAE 



fibrillar protoplasmic structure of the inner cells is still more marked at this late stage than before 
and is most distinctly seen in the distal part of the developing organ. — I did not succeed in finding 
a fully formed seminal duct. 

We have now the question: from which cell layer arise the inner cells of the duct, are they 
ectodermal or endodermal? The question cannot be answered on the basis of the present investigations 
If Hickson's view were correct, that the spermarium of the gonophore is surrounded by a thin endoderm 
layer, their origin from the endoderm would be a consequence. But the investigations give no support 
to this view and it is contradicted by Hickson's own figure (1891 PL 30 fig. 15) of the yong gono- 
phore in Dislichopora. The endodermal layer round the spermarium might be a later formation, but 
this theory does not find any support either in the present investigation. Provisionally therefore the 
question of the origin of the inner cells in the seminal duct must remain unanswered. 

The female gonophores agree down to the smallest detail with those of Stylasfcr gciiiinasccns. 
The mature egg is surrounded by an ectodermal layer and in Stylastcr iiorvegiats no indication can 
be found either of an endodermal layer between the egg-cell and the ectoderm, as Hickson (1891 
p. 390) has found to be the case in Disticliopora. During the development of the &%% the spadix 
atrophies and the pictures obtained of the condition in Stylastcr gcviviasceits (PL V figs. 46. 29 and 50) 
are fully illustrative of tlie conditions in Stylastcr norvegiciis. Here also I did not succeed in finding 
the young developmental stages of the female gonophore. 

The first description of the species is found in a pajicr of G u n n er u s (1768 p. 64), who calls it Millc- 
pora norvegica. In an appendix (1. c. p. 67) he states that the .species is identical with Millrpora aspcra 
which Liune described somewhat later in tlie nth edition of the Systema naturae. The original 
specimens of Gunner us are preserved in the Zoological Museum of Trondhjem; one of them is 
represented in fig. 12 PI. II. — It is doubtful if it really is the same species which is described by 
Ehrenberg under the name of Allopora oculina. In Milne-Edwards' diagnosis of the latter 
species (1857 p. 132) we find: sCoenenchyme tres-developpe, convert de points tres-serres, visible seulement 
avec des verres grossissants«. This does not agree with the quite smooth surface, which is characteristic 
of Stylastcr (Allopora) norvegictis. On the otlier hand, the .specimens which are sometimes referred to 
in the literature from the Norwegian west coast under the name of Allopora ocnliiia are undoubtedl\- 
identical with Stylastcr norvegicus, the onh- Allopora met with in the northern Atlantic. It is this 
species which formed the basis of G. O. Sars' cla,s.sical investigations (1873 p. 45), in which he restores 
the specific name of Gunner us but refers it to the genus Allopora; he is of opinion that the species 
is identical with Ehrenberg's Allopora oculina. G. O. Sars was the first to describe the conditions 
in a living Stylasterid, after studying colonies of Stylastcr norvegicus out on Storeggen on the west 
coast of Norway. He was in doubt as to tlie coralline nature of the animal, as he never succeeded 
in observing the extended polyps, when the colonies were at rest in sea-water, as is the case in our 
northern corals otherwise, and when he later studied the preserved animal somewhat more closely he ex- 
pressed his opinion (1. c. p. 46): »though I am far from considering this ') as completed, >et I ha\e already 
learnt this much, that tlie animal is es.sentially different from tlie other corals and probalilv does not belong 
at all to the Antliozoa but rather to the Hydrozoa'i. As is well-known, Moseley a year later (187.SI 

') i. e. Uk- investigation. 



STYIvASTERIDAE ig 



confirmed the correctness of Sars' sujjposition. — Since Storm {1882 p. 169) some years later mentioned 
tlie occurrence of the species in the Trondhjem Fjord, we find httle or nothing in the Hterature regarding 
its occurrence on the west coast of Norway. 

The species has been figured however by P- M. Duncan (1874 PI. 49 figs, i — 3) from material 
from the : Porcupine^ ; the identity of the colon\- from the figures given cannot be doubted, though 
the author refers it erroneously to Sfy/asfrr gnniiKisLi-iis. Moseley (1881 p. 85) notes the species under 
the name of Allopora ocuUna\ Hick son (1888 p. 594) mentions the species from the Hardanger Fjord 
as Allopora oculiria and from the Triton« Expedition as Allopora iiorvegica. Apart from the doubt 
whether the two species belong together, the present species must in any case under the international 
rules of nomenclature retain the specific name which was given it already by Gun nerus in the year 1768. 

Remarks on the affinities and systematic position 

of the Hydrocorallines. 

After L. Agassiz in 1859 had pointed out the Hydroid nature of the Milhpora and Moseley 
in 1878 had indicated, that the organisation of the Stylasterids also characterised them as Ifydrozoa, 
no one has doubted that the Hydrocorallines are most nearly related to the Hydroids and in reality 
must be regarded as highly specialised Hydroids, whose main characters are the power of the colony 
to form a skeleton of calcium carbonate and the polymorphic development of their polyps. 
These are thus the main characters which mark off Moseley's order Hydrocoralliiiac. 

Closer consideration of these characters entitles us to doubt, however, whether on such a basis 
we are justified in raising the H\drocorallines to the rank of a special order. If we compare them 
for example with the large order of corals, we see how the greater or less ability of the colonies to 
separate out carbonate of lime — as for example in the Uinbellula species — is only regarded as a specific 
character and is not even sufficient for a generic separation of the species, unless the lime-excreting function 
is combined with distinct morphological changes in the individuals or colonies. It is thus a question, whether 
the latter is the case or not when we compare the Hydrocorallines with the Hydroids. We must therefore in 
the first place endeavour to ascertain, to which of the Hydroids the Hydrocorallines are most closely related. 

The first hint is obtained from the tectonic structure of the colony itself. The fine anastomosing 
canals of the decalcified Hydrocoralline are quite homologous with the stolons of the Hydroid colony; 
we thus remark a conspicuous resemblance between the Stylastcridae and the Hydroceratinidac % 
Even the structure of the colony agrees exacth- in Clathrozooii Wilsoni Spencer and the primitive 
Stylastcridae, only the chitin of the skeleton being replaced in the Stylastcridae by a thick layer of 
calcium carbonate. Another H>-droid group also, Solanderiinac (family of Corynidac, cf. Kiihn 1913) 
shows the same structure of the colony and can be imagined as standing near the parent stem of the 
Hydrocorallines. 

The structure of the polyp will perhaps show the further line of comiection. Most Hydroid 
investigators lay great stress systematically on the form of the tentacles and consider them one of the 
principal phylogenetic characters. Moseley (1881 p. 46) maintains, that the tentacles of the Hydro- 

I) By Kiihn (1913 p. 228) the HydroceratiniJac are considered a subfamily of Botigainvilliidae. 

3* 



20 STYLASTERIDAE 



corallines, where they occur, are capitate or rather »kiiobbed at their tips . Closer comparison of his 
drawings and of the figures later authors have given indicates, however, that the Stylasteridac do not 
have capitate tentacles like the Corymidae, even though the cuidocysts are accumulated more densely 
in the distal part of the tentacles. It has been pointed out several times in the foregoing, that the 
tentacles in the northern Stylasteridac fully agree in their structure with the thread-shaped tentacles 
of the Bougainvilliidae. On the other hand, the Millcporidae liave typical, capitate Corynid tentacles. 
This suggests that the Hydrocorallines have a diphyletic origin and that the excretion of a calcareous 
skeleton in the two groups is purely a character of convergence. This witnesses further to the 
correctness of the .separation of the Hydrocorallines into two families, as is done by Hicks on and 
England (1905 p. i.). On the other hand, we are not entitled to regard the two groups as sub-orders 
we should rather consider them as two highly speciaHsed Hy-droid families. Hick son and England 
take the Milleporidac as Hydroids, whilst they regard the Stylasteridac as most nearly related to the 
Trachomedusae; what support they ma\- have for this last view, does not appear anywhere in their 
works; the consequence is, that Hickson in his contribution to The Cambrigde Natural History* 
(1906) discusses the two families at widely separated places. — The structure of the gasterozooid in 
the Stylasterid genera as in Sporadopora and still more Erriiia agrees fulh- with tlie polyp of the 
Bougainvilliidae; excluding the gasterostyle, which phylogenetically must be of fairly recent origin and 
which does not occur either in all Stylasterids, the gasterozooids of the Stylasteridac fully agree with 
the polyps of Clafhrozoon. This indicates, that the latter genus contains the nearest allies of the 
Stylasteridac among the Hydroids. 

The second main character, the polymoriDhic development of the polyps in the Stylasteridac, 
we find already indicated in such BougainviUiidae as Hydractii/ia; in several species of these we find 
tentacle-less »feelers« and tentacle-bearing nutritive individuals. In the Hydractinia species this 
distinction is not considered a useful mark of generic separation, nor can it be considered so important 
a feature in the Stylasteridac, that it can form the basis for a separation of the group into a special 
order, even if the dimorphic development of the somatic individuals has become a constant character. 

We have hitherto directed attention exclusively to the somatic individuals, assuming that tliey 
give the most important supports in judging of the phylogeuetic conditions of the Coelenterates. — 
Hickson (1891) through his evidence of a medusa generation in Millcpora has produced the last 
incontrovertible proof of the Hydroid nature of this genus; the medusa seems to be an undoubted 
Anf/ioMcdzisa and thus shows clearly the close relationship with the Corynidac. On the other hand 
the Stylasteridae have sessile gonophores. Moseley (1881 p. 93) maintains that the gonophores 
of the Stylasteridae are »adelocodonic«; but he regards the .spadix of the female gonophores as an 
organ ( the trophodisc«) special to the Stylasteridae. Hickson later (1888 and 1891) has examined 
the gonophores more closely and supports Moseley's view, that the trophodisc is a special formation 
in the Stylasteridae which is no direct parallel to the spadix of the hydroid gonophores. 

If we consider the manifold nature of the development and organisation shown b\- the gono- 
phores of the Hydroids, the special character of tlie trophodisc and gonophores of the Stylasteridac 
becomes extremely doubtful. In his excellent studies on the hydroid gonophores (1910) Kiihn has 
shown, that the medusa reduction may be so complete, that even the endocodon nuiy disappear; thus 



STYLASTERIDAE 21 



only the mamibritini remains as spadix. In his figures (1888 PI. 38 figs. 4 and 6) Hickson has shown 
cases of such reduced gouophores in Distichopara and the northern Sfylastcr species also have similar 
gonophores. Even though such a gonophore structure has not yet been shown in the Bougainvilliidae, 
vet it is not without a parallel in the athecate 

Hydroids. In Eudend rutin racemosmii (Cavoliui) \ /;■_[ ^^j. 

the spadix is bifurcated into two or often three sp^ ^ 

branches, w-hich claw-like embrace the egg-cell \ 

(Text fig. E). This is in fact a simplified tropho- 

disc; an increase in the number of the spadix \ 

branchings would very soon lead to the condi- 
tion we have found in Sfylastcr roscus and the 

step from tliis to the condition in Sfylaslcr ' ^--sio 

gctninasccus and Stylaster norvcgiciis is also I II 

short. There is thus no fundamental difference Text-fig. I: Female Gonophore of £»</,■«<//•/«/« ™,v//mwwfCa vol ini) 

, 1 • 1 ■ .-i-- .1 • • r i.1. I.-1 1 from the .'\driatic (95/,) 'i. II: semidiagrauimatic figure of the 

present, which lustities the raismo- of the Sfyla- ^ , , \ i , 7 „ . 

r ' ■' o . female gonophore of stylaster rosnis. o = ovum, stk = stalk of 

steridac to a special order. the gonophore, jY(1j = main stolon of the gonophore, i/02:=secon- 

. dary stolon of the gonophore. sp = blind sacs of the spadix. 

There is one condition however to which 

Hickson ascribes even greater weight. In his work on the gonophores in Disficliopura and Allopora 

he states (1891 p. 392): 3 Comparing the adelocodonic gonophores (fig. 4) with the male gonophores of 

Allopora (fig. 5), two points of difference may be observed. In the first place the endoderm completely 

surrounds the gonad in the latter, excepting at a small aperture at the distal pole, where it forms the 

inner wall of a seminal duct. Secondh', there is no layer of ectoderm between this endoderm and the 

gonad of Distichopora. In the adelocodonic gonophore there are two la\ers of ectoderm between the 

gonad and the wall of the gonangium . 

Quite apart from the disagreements between Hickson's results and the present studies on the 
gonophore structure in the Stylasteridat\ his argumentation is hardly maintainable in the light of later 
studies on the gonophores of the Hydroids. In a species such as Coryiic fruticosa Kiihn (1910 p. 65, 
Taf. 6 figs. 25— 27) has shown, that the gonophores have just the structure which Hickson gives as 
characteristic of Distichopora and Allopora. It is thus not without a parallel in the Hydroids. Much 
more rare then is the still simpler gonophore type in the Hydroids, where the endodermal cell-layer 
has also disappeared; nor is this without a parallel however; according to Kiihn (1912 p. 199) it has 
been found in Gymnogonos crassicoriiis and in Eudendrium simplex. 

The only gonophore type in the Sfylastcridac, which in reality differs greatly from the known 
conditions in the Hydroids, is the male gonophore in Pliobothrus symiiicfricus. With its follicular 
structure this shows a higher stage in the gonophore structure than any other gonophore we as yet 
know from the lower Coelenterata. In reality we have here striking evidence of the fact, that the 
gonophore structure has been greatly overestimated in judging of the pliylogeny of the Hydrozoa ; 
one of the most primitively organised Stylasterids has the most | highly organised gonophore 
type of all. 

') After specimens from Triest kindly sent me by Hr. Dr. C. I^ehnliofer (Innsbruck). 



22 STYIvASTERIDAE 



In its Structure Pliobothrus shows several features which indicate, that it stands nearer to the 
origin of the Stylastcridae than most of the other Stylasterid genera. In tlie first place, the 
zooids are not yet collected into distinct cyclosystems but are irregularly scattered over the colon); 
no regularity in the occurrence of the gasterozooids and dactylozooids can be detected. In the second 
place, the dactylozooids are less reduced than in the other Stylasteridae, as they still retain their inner 
cavity; nor do the\- show the marked division between an expanded basal part attached to the skeleton 
and a distal tentacle-like part, which is inserted obliquely on the basal part, as in most of the other 
Stylastcridae. Lastly, the gasterozooids lack a gasterostyle. These features show, when taken together, 
that Pliobothrus occupies a primitive position. Pliobothrus shows further, that the conservative, somatic 
parts of the colony are less exposed to the influence of the surroundings, to adaptive tendencies, than the 
generative parts, the power of which to change plastically in gelation to the special biological demands 
is of vital importance for the existence of the species. In this therefore we also see the reason for 
the great variety displayed by the hydroid gonophores and in this we have the reason, why the 
gonophores of nearly allied species may be quite different. Owing to their conservatism in develop- 
ment the polyps are of the m ost import ant phylogenetic in teres t. The gonophores, the 
generative individuals, on the other hand, might almost be said to be a play-ball in 
the hands of chance biological conditions and thus phy logene ticall y have much less 
interest; they are suited to display the subdivision of the genera into biological adaptive groups 
and are thus more exposed to the influence of convergence than the other parts of the colonies. 

We must therefore not ascribe too great importance to the condition of the gonophores in 
judging of the affinities of the Stylastcridae in relation to the other Coelenterata. Their organisation 
according to the results of all investigations may well be compared with that of the Hydroid gonophores 
and even if a single genus shows somewhat special features, the\' can by no means be used as evidence 
for the view, that the Stylastcridae are more distantly related to the Hydroids than the Millcporidac. 

Bringing together the main points of the above discussion the result is, that we in reality 
cannot con.sider the Hydrocorallines as anything else but two convergent Hydroid families, which are 
characterised by their power to develop a skeleton of calcium carbonate and b\' the dimorphic development 
of their somatic individuals. The family Milleporidae traces its origin to that of the Coryuidac, whilst 
the Stylasferidae is a highly specialised branch which has been derived from the Bongainvilliidae. Just as 
the Corynidae are distinguished from the Bougamvillidae by their capitate tentacles, the Milleporidae 
with their capitate tentacles are distinct from the Stylastcridae, in which the tentacles are constructed 
like the thread-shaped tentacle type of the Buugainvilliidae. 

Zoogeographical remarks on the North Atlantic Stylasteridae. 

Few animal groups have been so little investigated in our northern waters as the Hydro- 
corallines. They do not form any prominent faunistic element, it is true, as they are only represented 
by four species in the northern Atlantic and of these, as known, only two penetrate into the Norwegian 
Sea. But by contrast these two species at several places form a very characteristic element in the 
large biocoenosis of the Lophohelia reefs and form here a complete and extremely interesting parallel 
to the numerous Stylasterid species of the tropical coral reefs. 



STYLA.STERIDAli 



23 



A very speaking example of how little attention has been paid to the Atlantic Stylasteridae 
on reference being made to the fannistic conditions of this ocean is fomid in a statement in Parker 
and HaswelTs Textbook of Zoology (1897 p. 147): The Hydrocorallinae occur only in the tropical 
portions of the Pacific and Indian Oceans, where they are found on the coral reefs < partly or entirely 
surrounding many of the islands in those seas.. Nevertheless, some of the oldest, quite identifiable 
descriptions of Stylasteridae are those given by Gunnerus in his work Om nogle norske 
Coraller« (1768). His figures leave no doubt as to the identity of the species and his originals, which 
all came from the west coast of Norway, are preserved in the Zoological Museum of Trondhjem. — 
The work of Gunnerus has been little known owing to tlie humble and little distributed journal 
in which the paper was published. But several papers have also been published later in which the 
Atlantic Stylasteridae are mentioned and here we must place in the first rank Pourtales' excellent 
work on the deep-sea corals (1871), in which he describes quite a number of Stylasterids from the 
American side of the Atlantic, especially from the waters round Florida. Pourtales described here 
tor the first time Pliobotltrus synniirtricus and also mentions a second of the North Atlantic species, 
Stylastcr roseus^ under the name of Stylaster erubesccus. In addition, we have still two other, old 
records from the North Atlantic. G. O. Sars (1871) has given a classic description of the living Allopora 
norvegica and P.M.Duncan (1874) mentions Stylasterids from the P'aeroe Channel. With exception 
of the work of Gunnerus all these papers are cited in detail by Moseley {1881) in his great work 
on the Stylasteridae of the >. Challenger . 

Later information regarding the northern Stylasterids is very meagre. Storm (1882) mentions 
Stylaster gemmaseens and Allopora norvegica from the Trondhjem Fjord; there is a casual remark by 
Hickson (1891), that he has had material of Allopora oculiua from the Hardanger Fjord and of 
Allopora norvegica from the »Triton< Expedition; lastly, J.A.Thomson (1910) informs u.s, that he 
has examined colonies of Stylaster from Rockall. 

On the basis of the literature, therefore, we cannot penetrate very far into the biogeographical 
conditions of the northern Stylasterids. In this respect the comparatively large material collected by 
the Ingolf , »Thor« and the East Greenland Expedition of 1900 fills up a large gap in oui knowledge. 
Supplementing this material with that preserved in the museums of Christiania and Trondhjem and 
further with observations from the Trondhjem Fjord we are able to throw a fairly good light on the 
biogeographical conditions of this enigmatical group in our northern waters. 

As alread\- noted, the Stylasteridae in the Norwegian Sea are t>pical coral reef dwellers. 
Yet at places in the Trondhjem Fjord Stylaster geiinnascois is able to live in somewhat shallower 
water, sometimes even in towards a depth of 50 metres. This must depend on the special biophysical 
conditions of the fjord and it is of interest to note in this connection, that according to the investigations 
the species is only able to live in the shallower parts at places where projecting, submarine cliffs or 
barriers force the masses of water upwards which are brought in by the tidal wave. The shallowest 
occurrence of the species lies near its innermost boundary in the fjord. In the outer parts of the fjord, 
on the other hand, where the sides of the fjord are steeper and more regular, the species as also 
Stylaster [Allopora) norvegicns is bound to the Lophohelia reefs and both species here as elsewhere 



24 



STYLASTERIDAE 



must be regarded as characteristic forms of the large biocoenosis of the coral reefs. This is also 
strengthened by the single discover}' of Stylastcr gcmniascrns made in the Hjelte Fjord in the 
ighbourhood of Bergen, where Dr. O. Nordgaard has obtained two small fragments of colonies 



ne 



from the coral reef there. 

We thus see that the two Stylastcr species which occur on the coast of Norway, form interesting 
parallels in the animal community of the northern coral reefs to the Stylasterids of the tropical coral 
reefs. They are thu.s, like the Lophohclia reefs as a whole, bound in their occurrence to those localities 
witii hard bottom, where the Atlantic current makes its influence most felt in the Norwegian Sea. 




A Pliohothnts syntmetrit'iis 

A — — iiicompl. geograph. data. 

9 Stylastcr gemmasceiis 

O — rosau 

+ — (Allopora) norvegicus 

Text-fig. I''. Map showing tlie localities of the Styhntevidac in the North Atlantic and the Norwegian Sea. 



200 ni. depth 
600 - — 
1300 - — 



The study of the occurrence of the North Atlantic Stylasterids shows several biogeographical 
features of interest (cf. Chart Text-fig. F). — Pliobothrus symmetricus was first described from the waters 
round about F'lorida and must be fairly connnon there between 190 and 300 metres. It has been found 
by the »Ingolf« on the steep slope off the south coast of Iceland towards the depths of the Atlantic 
in 594 and 658 metres. According to Duncan (1874 p. 336) the ;> Porcupines obtained a single specimen 
in the cold area of the Faeroe Channel; unfortunately he does not state the exact locality. We thus 
have a species here which Ijelongs to the warm Atlantic waters and uormalh- is not able to penetrate 
in over the submarine ridge, which towards the south separates the Norwegian Sea from the depths 
of the Atlantic. The (juc- find in the cold area must be a pure chance and forms a parallel to the 
single and scattered finds which have been made here and there in the Norwegian Sea of other 
typical warm water forms anii>ng the Ilydroids. 



STYLASTKRIDAH 



25 



Stylastrr roscits forms a parallel to Pliobotlinis synnnetricus. It is fairly comiiioii between 230 
and 620 metres at Florida and on the whole has probably a greater bathymetric distribution than 
Pliobothrits syiiiiiiefricus. Sfylasfcr roscits is much more frequent in its occurrence than the latter form, 
but is restricted in the Atlantic to the south of the submarine ridges and has not yet been found in 
the Norwegian Sea. The ;Ingolf« has taken the species at a single place in the Denmark Strait in 
water of negative temperature; this occurrence is due probably to a submarine wave making the 
conditions inhabitable for the species when it became attached as larva or that the station at the time of 
observation was covered b\- a wave of the cold polar water — In the Norwegian Sea the species is 
replaced by the nearly allied Sfylasfer gciiiiiiascci/s, which in reality must be ranged with the extremely 
few animals, which are entirely bound to the warmer layers of the Norwegian Sea. We may feel tempted 
to consider it a biologicalh' defined, local species, which has divided off from Stylaster roseus. The 
two species have only been found side by side with certainty at the above-mentioned boundary station 
in the Denmark Strait, where the line of separation must be drawn between the Atlantic deep-water 
region and the boreal water-layers. This is the only time that Stylaster gemmascens has also been 
found in water of negative temperature. Once the species has been identified with certainty south of 
the Wvville-Thomson ridge, a couples of colonies being found at Rockall; the fauna at Rockall however 
has a strong mixture of species, whose chief occurrence is bound to the Norwegian Sea. 

Finally, the last species Stylaster norvegicus is an Atlantic species which belongs to the North 
Atlantic and has been able to penetrate into the Norwegian Sea, where it has found a new home in 
the warmer water-layers there. Its occurrence shows a secondary centre in the Trondhjem Fjord, 
where along with Stylaster gcmiiiasceiis it is more abundant than anywhere else in the northern parts 
of the Atlantic. The occurrence of the species in more southern waters cannot be accepted as certain, 
for its systematic characters have hitherto been too little unravelled; but it can hardly be very 
common there. 



Troudhjem, November 1913. 



Tile Ingolf-Expedition. V. 5. 



LITERATURE 

1. Arndt, W , 1912: Zoologische Ergebnisse der ersten Lehr-Expedition der Dr. P. Schottlandersclien Jiibilauins Stiftuiis;. 

(Jahresber. Schles. Gesellch. vaterl. Cultur 191 2) Breslau. 

2. Duncau, P. M. (1874): A description of the Madreporaria dredged up during the Expeditious of H. W. S. "Porcupine" 

in 1869 and 1870. (Transact. Zool. Soc. London Vol. VIII) Loudon. 

3. Esper, E. J. C. (1797): Fortsetzungen der Pflanzenthiere, Theil i. Niirnberg. 

4. Greeff, R. (1886): Ueber westafrikanische vStylasteriden. (Sitzungsber. Ges. Beford. gesamt Naturwiss. Marburg, Jahrg. 

1 886) Marburg. 

5. Gunnerus, J. E. (1767): Oni nogle norske Coraller. (Det kgl. norske Videnskabers SeLskabs Skrifter, 4de Deel) 

Kiobenhavn. 

6. Hickson Sydue)', J. (1888): On the Maturation of the Ovum and the Early .Stages in ths Development of AUopora. 

(Quarterly Journ. Micr. Sci. Vol. XXIX) Loudon. 

7. — (1891): The Medusas of Millepora murrayi and the Gonophores of AUopora and Distichopora. (Quarterly Journal 

Micr. Sci. Vol. XXXII) London. 

8. — (1906): Coelenterata & Ctenophora. (The Cambridge Natural History Vol. I) London. 

9. — (1912): On the Hydrocoralline Genus, Errina. (Proc. Zool. Soc. Loudon 1912) London. 

10. — and England, Helen M. (1905): The Stylasteriua of the Siboga Expedition. (Siboga-Expeditie, Monogr. VIII) 

Leiden. 

11. — and England, Helen M. (1909): The Stylasteriua of the Indian Ocean, in: The Percy Sladen Trust Expedition. 

(Transact. Linnean Soc. London Ser. Zoology vol. XII) London. 

12. Kiihn, Alfred (1910): Die Entwickeluug der Geschlechtsindividuen der Ltydroniedusen. (Zool. Jahrb. Abt. Anatomic, 

Bd. 30) Jena. 

13. — (1913): Ent-wickelungsgeschichte uud Verwaudtschaftsbeziehungen der Hydrozoen. I. Die Hydroiden. (Ergebn. u. 

Fortscbr. der Zool. Bd. IV) Jena. 

14. Lindstroui, G. (1876): Contributions to the Actiuology of the Atlantic Ocean. (Kongl. svenska Vetenskaps-Akademiens 

Handlingar, Ny Foljd. Bd. 14) Stockholm. 

15. Marenzeller, Emil v. (1904): Stein- uud Hydro-Korallen. (Bull. Mus. Conip. Zool. vol. XLHI) Cambridge, Mass. 

16. — (1903): Madreporaria uud HydrocoraUia. (Exped. Antarct. Beige) Anvers. 

17. Milne-Edwards (1S57): Histoire naturelle des Coralliaires, Tome II. Paris. 

18. Moseley, H. N. (1878): On the structure of the Stylasterida;. (Phil. Trans. Roy. Soc. 187S) London. 

19. — (1S81): Report on certain Hydroid, Alcyonarian, and Madreporarian Corals. (Rep. Sci. Res. "Challenger", Zoology 

Vol. II) London. 

20. Nordgaard, O. (1912): Faunistiske og biologiske iakttagelser. (Det kgl. norske Vidensk. Selsk. Skrifter 1911) Trondhjeni. 

21. Pallas, P. S. (1766): Elenchus Zoophytornm. Hagse-Comitum. 

22. Parker, T. Jeffery and Haswell, William, A. (1897): A Textbook of Zoology Vol. I. Loudon. 

23. Pax, Ferdinand (1910): Die Steinkorallen. (Deutsche Siidpolar-Expedition 1901 — 1903 Bd. XII, Zool. IV) Beriin. 

24. Pourtales, L. F. de (1871): Deep-Sea Corals. (Illustr. Catalogue Mus. Comp. Zool. No. IV) Cambridge, Mass. 

25. _ (1S78): Corals and Crinoids in: Reports on the Dredging Operations of the U. S. Coast Survey Str. "Blake". (Bull. 

Mus. Comp. Zool. Vol. V) Cambridge, Mass. 

26. Sars, G. O. (1873): Bidrag til Kundskaben cm Dyrelivet paa vore Havbanker. (Vidensk.-Selsk. Forhandlinger for 1S72) 

Christiania. 

27. Schneider, K. C. (1902): Lehrbuch der vergleichenden Histologic der Tiere. Jena. 

28. Storm, V. (1879): Bidrag til Kuudskab om Throndhjemsfjordens Fauna. (Det kgl. norske Vidensk. Selsk. Skrifter 1878) 

Throndhjem. 

29. — ■ (1882): Bidrag til Kuudskab om Throndhjemsfjordens Fauna IV. |I)et kgl. norske Vidensk. Selsk. Skrifter 1881) 

Throndhjem. 

30. Thomson, J. Arthur (1910): Note on a Hydrocoralhne from Rockall. (Proceed. Roy. Phys. Soc. Edinburgh vol. XVIII) 

Edinburgh. 



EXPLANATION OF THE PLATES 

The following letters indicate the same parts in all Plates. 
Ae Ectodermal epithelium of the ampulla. Gp Gasteropore. 



Cn Cnidocysts. 
Dp Dactylopore. / 

D.s Dactylostyle. 
Ec Ectoderm. 
En Endoderm. 
e Ectodermal epithelium of the gastero- 
pore wall. 
Ge Ectoderm of the gonophore. 



Gs Gasterostyle. 
I The inner cells of the seminal duct. 
O egg cell. 
Sp Spadix. 
s Stolon. 
T Tentacle. 
t tabula. 
W Free wall of the gasterozooid. 



Plate I. 



Plate I. 

Fig. I. Pliohothnis syvivirfricits\ front surface of an intact colony from the "Ingolf St. 55. Natural size. 

— 2. — — hind surface of the same colony. Nat. size. 

— 3. — — two ends of branches from "Ingolf St. 55. 4/,. 

— 4. Stylastrr gemmascciis\ one of the type specimens of Giinnerus' Madrepora virgiiica from the 

west coast of Norway. Nat. size. 

— 5. Stylaster gemviascrns\ front surface of an openly built colony from the Trondhjem Fjord. 

Nat. size. 

— 6. Stylaster gemmascens\ hind surface of same colony. Nat. size. 

— 7. — — front surface of the compact branch of a fertile colony (J) from the 

Trondhjem Fjord. Nat. size. 

— 8. Stylaster roseits\ front surface of a fragment of a colony from Angmagsalik with male ampullae 

Nat. size. 
— 9. Stylaster rosctis; hind siu'face of the same fragment. Nat. size. 



The Ingolf Expedition, V, 5. 



Brock: Stylasteridw. Tab. I. 




HJ. Brocft phot. 



Nordenfjeldsks Klicheanstalt. 
Waldemar Janssens Boktrykkeri. 



Plate II. 



Plate 11. 

Fi<;. lo. Stylaster roscus; front surface of a fragment of a colony with female ampullae; "Ingolf vSt. 15. 
Nat. size. 

— II. Sty taster roseiis; fragment of a colony which is entirely deformed owing to the development 

of numerous female ampullae; "Ingolf" St. 7. Nat. size. 

— 12. Sty taster norvcgicus\ one of the type specimens of Gunner us' Alillcpora ■norvcgica from 

west coast of Norway. Nat. size. 

— 13. Sty taster norvegicits\ front surface of a narrow-branched colony from Trondhjem Fjord. Nat. size. 

— 14. — — hind surface of the same colony. Nat. size. 

— 15. — — front surface of a broad-branched colony from Trondhjem Fjord. Nat. size. 

— 16. — gemmascens\ ends of two branches of a colony from Trondhjem Fjord, ^/j. 

— 17. — rosetis\ end of a branch of a colony from "Ingolf" St. 15. I'l. 

— 18. — >wrvegicus\ ends of two branches of a colony from Trondhjem Fjord. 4/1. 



The Ingolf Expedition, V, 5. 



Broch: Stylasteridce. Tab. II. 




Hj. Broch phot. 



Nordenfjeldske Klicheanstalt . 
Waldemar Janssens Boktijkkeri. 



Plate III. 



Plate III. 

Fig. 19. Pliobollints syiiiiiictricus\ median longitudinal section of a branch point. "Vi- 

— 20. — — median section through a gasteropore with tabula, "'/j. 

— 21. Stylastcr geiniiiascrns; median longitudinal section of a branch, '"^/i- 

— 22. — rosciis; median longitudinal section of a branch. "='/,. 

— 23. — norvcgicus; longitudinal section through two cyclosystems. '^/,. 

— 24. Median, longitudinal, thin section of the gasterostyle in Stylaster gciiirnasccus. 9°/,. 

— 25. Longitudinal section of the gasterozooid in Stylaster geiuviascens. ^i°ji. 

— 26. Transverse section of the gasterozooid at the base of the tentacles in Stylastcr griiiiiiasccns. v'"/, 

— 27. Oblique transverse section of the gasterozooid at the base of the tentacles in Stylastcr 

norvegicus. 3°"/i. 
^ 28. Transverse section of the gasterozooid in Pliobothrus syniiiictricus. 300/j. 

— 29. Longitudinal section through the oral part of the gasterozooid wall in Pliobothrus syniiiic- 

tricus. 450/j. 

— 30. Longitudinal section through the oral part of the gasterozooid wall and tentacle in Stylastcr 

gemmascens. 'i^°/,. 

— 31. Longitudinal section through oral part of the gasterozooid wall and tentacle in Stylastcr 

norvegicus. 45°/;. 



Di^ 



The liigolf Expedition, V, 5. 

ap 

Dp 



dp 



% 



V-', 
r^.- 



■:H' 




Brocii: Stylasteridcp. Tab. III. 




^% K 



Hk 



v' r 



22. 



Gs 



19. 



Dp 



h 



Ds 



Ell 



tc 



23 a 



23 b 



24. 



Gs 



El- 

1 / 



r-^-Ci-.- 



Cf! 









25. 






» 

•v.. 









20. 



en 



En 



27. \ 



• v.. 



en 









2S. 






Ln 



.-' en 



29. 

Hj. Broch del. 






30. 



31. 

Sordmfjeldske Klichediistalt. 
Waldemar Janssens Doklrykkeri. 



Plate IV. 



Plate IV. 



Fig. 32. Transverse section of the gasterozooid at its base near its transition into the stolons in Sfylasfer 
gemmascens. i°°/j. 

— 33. Longitudinal section of the dactylozooid in Sfylasfer goiiiiiasccns. i°°/i. 

— 34. Transverse section of a dactylozooid in Pliohofhriis syvinietricus. i'^/i. 

— 35. Median longitudinal section of a very young gonophore (c?) in Sfylasfer iionugicus. 45'j/,. 

— 36. Median longitudinal section of a young gonophore (J") in Sfylasfer roscus. +5°/;. 

— 37. Median longitudinal section of an unripe gonophore {<$] in Sfylasfer norvegicus. 3«>/,. 

— 38. Median longitudinal section of two gonophores (tj*) in Sfylasfer norvegictts. The larger with 

spadix partially atrophied contains spermatocytes in process of transformation to sperma- 
tozoa. 13°/,. 

— 39. Median longitudinal section of a gonoi^hore (c?) in Sfylasfer roseus\ the spermatocytes in process 

of transformation to spermatozoa. '3"/,. 

— 40. Transverse section of a young gonophore (c^) in Pliobotliriis syiiniiefricus. 3°°/i. 

— 41. Median longitudinal section of a gonophore (c?) in Plioboflirits syj/iii/efricus. oo°/^. 

■ — 42. Median longitudinal section through apex of the full}' developed gonophore in (c?) Pliobofhriis 
symmetricus. 3°°/,. 



The Ingolf Expedition, V, 5. 



Broch : Sivlasteridce. Tab. IV. 






fn 



35. 



■Sp 



hn 



U' 



V. 



V 



32. 



Oe 



Ae 



G( 



33. 



34. 



3S. 



30. 



37. 



39. 



Sp 









Cie 









Ae 



4U. 



Hj. Broch del. 






Sp 






41. 



Si> 




/^ 



42. 



Nordenfjeldske KUcheanstalt. 
WaUUmar Janssens Boktrykkcri. 



Plate V, 



-nc. 



Plate V. 



Fig. 43. Apex of a o-onophorc (c?) in Stylastrr roscKs, containing- spermatocytes in process of trans- 
formation. ISO ,. 

— 44. Early stage in the development of a seminal dnet in Sfy/asfrr iiorvcgiciis. 450-'^. 

— 45. I^ongitudinal section throngh an almost fnll-grown, seminal dnet in Slylnstrr vori'rgiciis. i^"',. 

— 46. Median longitndinal section throngh a gonophore (5) with ripe ovnni in Stylnsfrr gi'iiiiiiascois. s™ ,. 

— 47. Median longitudinal section of a gonophore (^| with ripe ovum in Styhistrr rasriis. '^" ,. 

— 48. Transverse section of a gonophore ($) near the distal end of the spadix in Sf\lastrr rosnia. '3° ,. 

— 49. Trans\-erse section of the spadix close beneath the o\-um in St\lnstrr oniniiascrus. ^'=°i-t. 

— 50. Median longitudinal section tlirough a gonophore witii advanced plauula larva in Stylusicr 

ycnnii(i.s(ii/s. '^" ,. 



The IngoLf Expedition, V, 5. 
Ae 



43. 



Gc 



44. 



Ge 



Sp 



Brocli: StylasteridcK. Tab. V. 



Ge 



A,' 



45. 



<ji- 



Ge 



S,, 



47. 



./ 



46. 



O 






49. 



- Ge 



•>'\ 



Sp 



y 






Ge 



48. 

Hj. Brocli del. 



Sp 



50. 

Nordenfjeldske KUcheanslalt. 
Wiildemar Jaiisseris lloklrykkeri. 



THE INGOLF-EXPEDITION 



I895 — I896. 



THE LOCALITIES, DEPTHS, AND BOTTOMTEMPERATURES OF THE STATIONS 



Station 
Nr. 


Lat. N. 


Long. W 


Depth 

in 
Danish 
fathoms 


Bottom- 
temp. 


Station 
Nr. 


Lat. N 


Long.W. 


Depth 

in 
Danish 
fathoms 


Bottom- 
temp. 


Station 

Nr. 


Lat. N. 


Long.W. 


Depth 

in 
Danish 
fathoms 


Bottom- 
temp. 


I 


62° 30' 


8° 21 


132 


7°2 


24 


63° 06 


56° GO- 


1199 


2°4 


45 


61° 32 


9° 43' 


643 


4°i7 


2 


63° 04' 


9° 22 


262 


5°3 


25 


63° 30 


54° 25' 


582 


3°3 


46 


61° 32' 


11° 36' 


720 


2°40 


3 


63° 35' 


10° 24 


272 


o"5 




63° 51 


53° 03' 


136 




47 


61° 32' 


13° 40' 


950 


3°23 


4 


64° 07' 


11° 12 


237 


2°5 


26 


63" 57 


52° 41' 


34 


o°6 


48 


61° 32' 


15° II' 


1 150 


3°i7 


5 


64° 40' 


12° 09 


155 






64° 37 


54° 24' 


109 




49 


62° 07' 


15° 07' 


1 1 20 


2°9I 


6 


63° 43' 


14° 34 


90 


7°o 


27 


64° 54 


55° lo- 


393 


3°8 


50 


62° 43- 


15° 07' 


1 020 


3°'3 


7 


63^ 13' 


15° 41 


600 


4°5 


28 


65° 14 


ss" 42' 


420 


3°5 


51 


64° 15' 


14° 22' 


68 


7°32 


8 


63° 56' 


24° 40 


136 


6°o 


29 


65° 34 


54° 31' 


68 


0°2 


52 


63° 57' 


13° 32' 


420 


7°87 


9 


64° 18' 


27° 00 


295 


5°8 


30 


66° 50 


54° 28' 


22 


i°05 


53 


63° 15' 


15° 07' 


795 


3°o8 


lo 


64° 24' 


28° 50 


788 


3°5 


31 


66° 35 


55° 54' 


88 


i°6 


54 


63° 08' 


15° 40' 


691 


3°9 


II 


64° 34' 


31° 12 


1300 


i°6 


32 


66° 35 


56° 38' 


318 


3°9 


55 


63° 33' 


15° 02' 


316 


5°9 


12 


64° 38' 


32° 37 


1040 


o°3 


33 


67° 57 


55° 30' 


35 


o°8 


56 


64° 00' 


15° 09' 


68 


7°57 


13 


64° 47' 


34° 33 


622 


3°o 


34 


65° 17 


54° 17' 


55 




57 


63° 37' 


13° 02' 


350 


3°4 


14 


64° 45' 


35° 05 


176 


4°4 


35 


65° 16 


55° 05' 


362 


3°6 


58 


64° 25' 


12° 09' 


211 


0O8 


15 


66° 18' 


25° 59 


330 


-o°75 


36 


61° 50 


56° 21' 


1435 


i°S 


59 


65° 00' 


11° 16' 


310 


O"! 


i6 


65° 43' 


26° 58 


250 


6°i 


37 


60° 17 


54° 05' 


1715 


i°4 


60 


65° 09' 


12° 27' 


124 


o°9 


17 


62° 49' 


26° 55 


1 

745 


3°4 


38 


59° 12 


51° 05' 


1870 


i°3 


61 


65° 03' 


13° 06' 


55 


o°4 


i8 


61° 44' 


30° 29 


1135 


3°o 


39 


62° 00 


22° 38' 


865 


2°9 


62 


63° 18' 


19° 12' 


72 


7°92 


19 


60° 29' 


34° 14 


1566 


2°4 


40 


62° 00 


21° 36' 


845 


3°3 


63 


62° 40' 


19° 05' 


800 


4°o 


20 


58° 20' 


40° 48 


1695 


i°5 


1 


61° 39 


17° 10 


1245 


2°0 


64 


62° 06' 


19° 00' 


104 1 


3°' 


21 


58° 01' 


44° 45 


1 

1330 


2°4 


42 


61° 41 


10° 17' 


625 


o°4 


65 


61° 33' 


19° 00' 


1089 


3°o 


22 


58° lo- 


, 48° 25 


1845 


i°4 


43 


61° 42 


10° II' 


645 


o°o5 


66 


61° 33' 


20° 43' 


1 128 


3°3 


23 


60° 43' 


i 56° 00 

1 


Only the 
' Plankton-Net 
used 




44 


61° 42 


9° 36' 


545 


'" 


67 


61° 30' 


22° 30' 


975 





Station 
Nr. 


Lat. N. 


Long.W. 


Depth 

in 
Danish 
fathoms 


Bottom- 
temp. 


Station 
Nr. 


Lat. N. 


Long. W. 


Depth 

in 
Danish 
fathoms 


Bottom- 
temp. 


Station 
Nr. 


Lat. N 


Long. W. 


Depth 

in 
Danish 
fathoms 


Bottom- 
temp. 


68 


62° 06' 


22° 30' 


843 


3°4 


92 


64° 44' 


32° 52' 


976 


:°4 


118 


68° 27 


8° 20' 


1060 


-i°o 


69 


62° 40' 


22° 17' 


589 


3°9 


93 


64° 24' 


35° 14' 


767 


i°46 


119 


67° 53 


! 10° 19' 


lOIO 


-l°o 


70 


63=09' 


22° 05' 


134 


7°o 


94 


64° 56- 


36° 19' 


204 


4°r 


120 


67° 29 


II°32' 


S85 


— i°o 


71 


63° 46' 


22° 03' 


46 






65° 31' 


30° 45' 


213 




121 


66° 59 


13° 11' 


529 


-o°7 


72 


63° 12' 


23° 04' 


197 


6°7 


95 


65° 14' 


30° 39' 


752 


2°I 


122 


66° 42 


14° 44' 


"5 


i°8 


73 


62° 58' 


23° 28' 


486 


5°5 


96 


65° 24' 


29° 00' 


735 


I°2 


123 


66° 52 


15° 40' 


145 


2°o 


74 


62° 17' 


24° 36' 


695 


4°2 


97 


65° 28' 


27° 39' 


450 


5°5 


124 


67° 40 


15° 40' 


495 


-o°6 




61° 57' 


25° 35' 


761 




98 


65° 38' 


26° 27' 


138 


5°9 


125 


68° 08 


16° 02' 


729 


— o°8 




61° 28' 


25° 06' 


829 




99 


66" 13' 


25° 53' 


187 


6° I 


126 


67° 19 


15° 52' 


293 


-o°5 


75 


61° 28' 


26° 25' 


780 


4°3 


100 


66° 23' 


14° 02' 


59 


o°4 


127 


66° 33 


20^ 05' 


44 


5°6 


76 


60^ 50' 


26° 50' 


806 


4° I 


lOI 


66° 23' 


12° 05' 


537 


— o°7 


128 


66° 50 


20° 02' 


194 


o°6 


77 


60° 10' 


26- 59' 


951 


3°6 


102 


66° 23' 


10° 26' 


750 


~o°9 


129 


66° 35 


23° 47' 


117 


6°5 


78 


60° 3/ 


27° 52' 


799 


4°5 


103 


66° 23' 


8° 52' 


579 


-o°6 


130 


63° 00 


20° 40' 


338 


6°55 


79 


60° 52' 


28° 58' 


6S3 


4°4 


104 


66° 23' 


7=25' 


957 


-i°i 


131 


63° 00 


19° 09' 


698 


4°7 


80 


61° 02' 


29° 32' 


935 


4°o 


■05 


65° 34' 


7° 31' 


762 


-o°8 


132 


63° GO 


17° 04' 


747 


4°6 


81 


61° 44' 


27° 00' 


485 


6° I 


106 


65° 34' 


8° 54' 


447 


-o°6 


133 


63° 14 


11° 24' 


230 


2°2 


82 


61° 55' 


27° 28' 


824 


4° I 




65° 29' 


8° 40' 


466 




134 


62° 34 


■ 10° 26' 


299 


4° I 


83 


62° 25' 


28° 30' 


912 


3°5 


107 


65° 33' 


10° 28' 


492 


-o°3 


135 


62° 48 


9° 48' 


270 


o°4 




62° 36' 


26° 01' 


472 




108 


65° 30' 


12° 00' 


97 


i°i 


136 


63° 01 


9° II' 


256 


4°8 




62° 36' 


25° 30' 


401 




109 


65° 29' 


13° 25' 


38 


I "5 


137 


63° 14 


8°3i' 


297 


^o°6 


84 


62= 58' 


25° 24' 


633 


4°8 


no 


66° 44' 


11° 33' 


781 


— o°8 


138 


63° 26 


7° 56' 


471 


-o°6 


85 


63° 21' 


25° 21' 


170 




III 


67° 14' 


8° 48' 


860 


-o°9 


139 


63" 36 


7° 30' 


702 


-o°6 


86 


65° 03'6 


23° 476 


76 




112 


67° 57' 


6° 44' 


1267 


— i°i 


140 


63° 29 


6° 57' 


780 


-o°9 


87 


65° 02-3 


23° 56'. 


no 




113 


69° 31' 


7° 06' 


1309 


-i°o 


141 


63° 22 


: 6° 58' 


679 


-o°6 


88 


64° 58' 


24° 25' 


76 


6°9 


114 


70° 36' 


7° 29' 


773 


— i°o 


142 


63° 07 


7° 05' 


587 


-o°6 


89 


64° 45' 


27° 20' 


310 


8°4 


115 


70° 50' 


8° 29' 


86 


o°i 


143 


62° 58 


7°09' 


388 


-o°4 


90 


64° 45' 


29° 06' 


568 


4°4 


116 


70° 05' 


8° 26' 


371 


-o°4 


144 


62° 49 


7° 12' 


276 


i°6 


91 


64° 44' 


3i°C)o' 


1236 


3° I 


117 


69° 13' 


8° 23' 


1003 


i°o 













'0*<r: 



THE DANISH INGOLF-EXPEDITION, 



VOLUME V. 



HYDROIDA. 

(PART I.) 



BY 



HJALMAR BROCH. 



WITH 2 PLATES AND 20 FIGURES IN THE TEXT. 



->^>-::?<f<- 




COPENHAGEN. 

PRINTED BY BIANCO LUNO. 
I916. 



CONTE 



Preface I 

I. Introductory Notes 3 

a. The Hydroid Gonophores bearing on classification . 4 

b. The comparative anatomy of the nourishing individ- 
uals and the system of the athecate hydroids 7 

II. Athecate Hydroids of the northern Atlantic 11 

Section Capitata II 

Family Corynidac 11 

CoryKf Gaertn er 13 

Coryne Sarsii ( Loven ) 14 

— Loveni (M. Sars) 15 

— piisilla Gaertner 16 

— sp. aff. Hincksi Bonuevie iS 

Family Myriothelidae 18 

Myriothela M. Sars 19 

Myriothela phrygia (Fabricius) 19 

Family Ttibulariidae 21 

Ttiiularia Linne 22 

Tubularia ptdcJier (Ssemundss on ) 22 

— indivisa Linne 24 

— regalis Boeck 25 

— larynx El lis et Solander 27 

— sp. indet , 28 

Corymorpha M. S a rs 29 

Coryniorpha nutans M. S a rs 31 

— glactalis M. S ars 32 

— grooilandica { A 1 1 m a n ) 33 j 



NTS 

Corymorpha sp. indet 37 

Section Filifera 38 

Family Clavidae 38 

Clava G m e 1 i n 38 

Clava miilticornis ( F o r s k a 1 ) 38 

Merona Norman 40 

Merona cornucopiae Norman 40 

Monohrachhim M eres chko \vs k v 42 

Monohrachht7n^para$itiim M ereschkowskj' 42 

Family Boitgainvilliidae 43 

Hydractinia v a':i B e 11 e d e n 44 

Hydractinia Sarsii Steenstrup 45 

— echinata (Fleming) 46 

— Carica Bergh 48 

Bougainvillia Lesson 49 

'" ' : Bougainvillia conferta (Ald.er) 50 

Perigonimus M. S a rs 5' 

Perigonimus rcpcns ( Wright) 52 

— abyssi G. O. Sars 53 

— roseus ( JI. S a rs ) 54 

Family Ettdendriidae 5^ 

Eudendrium Ehrenberg 57 

Eudendriiim rametim (Palla s) 57 

— ramosnm (Linne) 59 

— VVrighti Hartlaub 60 

— annulalum Norman 62 

— capillare .A. 1 d e r 62 



Preface. 

The investigation of the large Danish collections of hydroids from the Faroe Islands, Iceland, 
and Greenland, and the researches into the interesting material bronght home from the In golf 
Expedition, have realised great resnlts. In fact, several points of dispnte as to the classification of 
northern species have been settled. In the first place, the Danish collections contain original specimens 
of some species which have been described as new sevei'al times after being originally recorded. In 
other cases, the large number of specimens tend to bridge the division between species which have 
hitherto been looked upon as "good" ones. It is, indeed, a matter of regret that deficiencies of diagnosis 
and inaccuracy of design have frequently put obstacles to the recognition of species previously recorded, 
and that the literature has, consequently, been encumbered with synonyms which we should rather 
have done without. This inconvenience, in fact, enforces the necessity of giving full and exhaustive 
accounts of every single species. The American investigators, indeed, on the pattern of Nutting 
have long tried to give brief diagnoses and drawings of all American species. But it must be observed 
that, because of the impressionist way of drawing, the illustrations are, as a general rule, somewhat 
wanting in accuracy, and to the brief diagnoses there is the objection that they are often too sunnnary 
to give exhaustive account of the distinguishing features. On the whole such weak points as appear 
in the last works of Alhnan, have gone down to his epigones. Great difficulties, indeed, are in this 
way given to students of the geographical distribution of the hydroids. No doubt, more species than 
those which are at present pointed out by literature, are common to the European and the American 
seas. But in general it proves impossible to form, on the ground of the brief diagnoses, a well-founded 
opinion as to the virtual qualities of many species. As far as the European species are concerned, we 
are fortunate in possessing the classic work of Hi neks, A History of the British Zoophytes. However, 
since the appearance of that work, plent>- of fresh subjects have been added by descriptions of several 
species and genera which can hardly all be maintained, and publications ha\e of late appeared in such 
abundance that it proves difficult to students of this group of animals to find their way through tlie 
crowded matter. 

These are the reasons why I have tried to give new and detailed diagnoses of every single 
species in question. The diagnoses are essentiall)' founded on the copious material occurring in the 
Danish collections. Of synonyms I have only selected those of absolute necessity. Detailed accounts 
of synonymy are found — as far as earlier literature is concerned — in the excellent treatises of Be dot, 

The Ingolf-Expedition. V. 6. 



HYDROIDA 



Materiaux pour servir a I'histoire des Hydroi'des, and — regarding recent literature on northern 
hydroids — in the groiqDings framed by Jaderholm (1909), Broch (1909), and Kramp (1914). As far 
as possible, the various species are accompanied by maps illustrative of the geographical data in the 
northern Atlantic. Besides the collections the recent literature has served as basis. In this respect 
the groupings occurring in the works of Bonnevie (1899), Jaderholm (1909), Broch (1909), Sce- 
niundsson (1911), and Kramp {1914), have proved particularly available. 

I have made it a point to define precisely the limits of genera and families by full diagnoses, 
and at the same time I have tried to account for the leading principles I hold to for the purpose of 
division and classification. The various authors have maintained various opinions as to the systematic 
principles of classification ; many of them have disregarded j^hylogeny and allowed biological considera- 
tions to play a predominant part; consequently the circumscription of genera has been practised in 
most various ways. To leave no opening for misunderstanding I have thought it necessary to give 
a detailed account of each species in question, even if the work should be delayed and grow a little 
broader than I wanted. However, I hope that in this way the extensive and methodical Danish col- 
lections will tell better and to fuller advantage than otherwise. 

Trondhjem the 22vd August igi^. 



I. Introductory Notes. 

Scarce!)- in any other part of the animal world greater difficnlties are tlirown in the way of 
the systematist than those occasioned by the lowest Coelenterata, impeding the attempts to establish 
a natural grouping of the hydroids and their attendants, the hydromedusa;. This is due not only to 
the actual deficiencies of our knowledge of these low organisms, but also to the fact — as pointed 
out by Kiihn in his excellent summary (1913) — that the groups present partly a confused series of 
adaptations and phenomena of convergency, partly the occurrence of medusa; of widely divergent 
development as companions of closely allied hydroids or, vice versa, closely allied niedusse accompanying 
hydroid polyps divergently developed. It is a striking fact that in certain species, for instance the 
Codonida-^ the phylogenetic development and differentiation of form of the medusae have been com- 
paratively stunted, whereas the polyps [Corynida^ Pcnnariidce, TubtilariidcE) have developed hetero- 
geneously so as to present a large series of various forms. The exact reverse is represented 
by the homogeneous polyps of the family Bougainvilliida forming the nurse generation of tlie hetero- 
geneously developed hydromedusfe of the families Margelida and Tiaridce. The possibiHty of construct- 
ing a safe system common to medusae and hydroid polyps, indeed, appears remote. For in the first 
place the two "generations", on account of their excessive abundance of species, have had to be treated 
separately, each generation by specialists of its own, and moreover, we are in fact still in the dark as 
to which of the two generations is to be regarded as the primitive or the phylogenetically older. 

When looked upon as a whole the group of Zoophytes must be characterized as a very low 
group of animals. In the nurse generation as well as in the free-swiniming medusae the structure 
of the individual is very simple, though the medusae after all must be said to be a little higher 
organised than the polyps. In addition to the two primary layers of cells, the endoderm and the ecto- 
derm, ocoirs in the medusje a "mesogloea", whose descent from one or the other of the primary layers 
is not yet definitely ascertained as far as all species are concerned. However, a mesogloea also occurs 
with some hydroids, for instance the "parenchyma" of the TubulariidcB, which is a typical endodermal 
formation. 

To students of the hydroids it very soon becomes obvious that the leading systematic characters 
have been derived from such criteria as urge themselves on a superficial view of the animals, while, 
contrarily to the method practised in investigating most other groups of animals, the inner 
anatomy is all but entirely left out of account. This is due to the generally accepted view that the 



HYDROIDA 



Structure of the hydropolyps is throughout quite homogeneous and accordingly affords no liolds of 
use to the systematist. A careful study, however, of the slight information occurring in the literature as 
to the structure of the polyps, will show that the old view is wrong. In this connection it will he 
sufficient to refer to the excellent passage written by Kixhn (1913), Die Ausbildung des Polypenkorpers, 
in which are mentioned several examples of the heterogeneous structure of the polyps in the various 

groups of hydroids. 

Nevertheless Kiilin himself (1913), in constructing his system of the hydroids, has, according 
to the old practice, left this fact almost wholly out of account. I will afterwards come back to the 
subject and point out how unreasonable it is to set aside this part of systematics even though a 
thorough investigation of the anatomy of the polyps may seem almost impracticable because of the 
state of preservation in which the hydroids generally occur in the materials of the great expeditions 
and collections. In fact, it is confirmed that Levinsen (1893) is right, emphasizing that the systematist 
in treating of hydroids should rather lay stress on all about the nourishing individuals than on the 
varying development and organisation of the generative individuals. 

a. The Hydroid Gonophores bearing on classification. 

Our knowledge of the hydroids has advanced a vast stride ahead owing to the thorough 
researches of Kiihn into the development and the organisation of the gonophores (1910). As to the 
importance of the gonophores to systematics, it has lately (1913) been asserted by the same author 
that no weight whatever can be given to the various gonophoral development, but that particular 
stress should be laid on the structure of the full-grown gonophores. On account of difference of structure 
he distinguishes between four types of sessile gonophores: eumedusoids, cryptomedusoids, heteromedusoids, 
and, finally, the simple gonophores, called styloids (Bonne vie 1898). The eumedusoid gonophores, indeed, 
retain the structure of the medusa throughout, and occasionally breaking away [Campanularia Integra 
Mc. Gillivr. — Agastra mira Hartlaub) occur like defective medusae. The structure of the crypto- 
niedusoid gonophores is more reduced. Certainly they keep their endocodon and their umbrellary cavity, 
but have a single-layered umbrellary endoderm; however, also of cryptomedusoids occur exceptional 
instances breaking away, as in Pachycordylc Weismanm Hargitt. The heteromedusoids are entirely 
wanting the umbrellary endoderm, and the inner umbrellary ectoderm is formed by delamination, not 
by invagination of the outer ectoderm (endocodon). The simplest gonophores, finally, are without any 
trace of medusoid organisation. These four types of sessil gonophores Kiihu (1913) regards as char- 
acters important to the systematist for the division of hydroids into genera. 

Stechow (1913) in his important work on Japanese hydroids occupies another standpoint, 
attaching more importance to the conditions of the gonophores. Thus he draws nearer to earlier 
])rinciples of classification, but at the same time he tries to make his systematic division more manage- 
able by drawing out characters from the outward morphology of the colonies, thus effecting the 
transition to the American school. The Americans, headed by Nutting, look on classification only as 
"a matter of convenience", and accordingly in their grouping.s, as a matter of fact, relinquish the idea 
of constructing a natural system aiming at summing up and drawing by critical sifting of the char- 
acters a skeletonlike picture of the phylogenetic affinities of the group of animals in question. Con- 



HYDROIDA 



sequeiitly the s\-.stem brought about by the American investigators, picking up heterogeneous char- 
acters, is indeed, as I have shown in an earUer treatise (1909), to a great extent one of arbitrariness, 
placing the species now in one, now in another genus, according to the character it is thought desir- 
able to emphasize at the moment. The system has, in this way, become a matter of chance. 

Before proceeding to the special explanation of the several species of hydroids and their occur- 
rence in the seas of the northern Atlantic, we, therefore, must try to realize, from a systematic and 
phylogenetic point of view, the value of each single character. In the first instance the question must 
be answered what part the gonophores play as to the phylogeny of the hydroids or, in other words, 
what importance has to be attached to the gonophores and their conditions for the purpose of 
classification. 

The application of the characters of the gonophores as distinguishing marks of higher system- 
atic unities, of families, or of subfamilies, has been abandoned by all modern investigators of the 
hydroids. On the other hand, it is held by several investigators that they are of importance as to the 
limitation of genera. The last significant publications maintaining this view, are those of Kuhn (1913) 
and Stechow (1913). Kiihn, liowever, applies the characters of the gonophores with much caution 
and discretion, while Stechow, as a glance at his tables (1913, p. 36 and tlie following pages) suffices 
to show, undiscerningly recurs to the principle of laying the main stress on tlie "medusa" as contrasted 
with the "sporosac". In fact, as long as the limits between these designations are not more precisely 
defined, they will be subject to much arbitrariness. An interesting instance is afforded by the point 
in dispute, where the limits are to be drawn between the genera Corync and Syncorync. The old 
criterion, accepted by All man and other investigators, was the free medusa as contrasted with the 
fixed gonophore or sporosac, and, to all appearance, it is the same limitation Stechow tries to 
maintain in his table. Indeed, this principle of limitation was only supportable on the ground of the 
deficient knowledge of the organisation and de\elopment of tlie liydroid gonophores attained to in 
AUman's days. Kiihn, therefore, (1913, p. 229) is seen to take quite another departure, defining the 
Syncorync as including all species having "medusae", wliile the Coryne is distinguished by styloid 
gonophores. It is evident from Kiihn's previous argument (I.e. p. 174) that imder "mednsfe" he also 
includes the eumedusoids which normally do not break loose, and that accordingly Coryne, in his 
opinion, exclusively embraces species having styloid gonophores. 

Parallel to these genera Stechow also treats of Podocoryne (with medusre) and oi Hydractinia 
(with "sporosacs"). Kiihn (1913, p. 227) groups them in the following vague way: 

o ocoryne 1 j^^^^^^^^^^ (Margelinen), Eumedusoide, Cryptomedusoide, Styloide. 
Hydractinia J 
From his premises (1. c. p. 226) it appears that he agrees with most modern investigators, think- 
ing it right that the two old genera should be merged into one, Hydractinia; for he states that m 
fact we have here before us a series of closely allied forms, in which "zwischen Arten mit Vollmedusen 
und einfachen Medusoiden die verschiedensten Ubergange bestehen". Thus Kiihn, elsewhere considering 
the characters of the gonophores as significant generic criteria, in this place actually reduces them 
to mere specific characters. 

In another connection Kiihn (1913 p. 197) gives an instance of the fact that the sexes m 



HYDROIDA 



one and the same species can be distinguished by different t>pes of gonophores; thus the female 
gonophore of Laomedea flexuosa Hi neks is heteromedusoid, while the male gonophore is styloid. 
This strongly defined sexual dimorphism is most interesting, and the question is obvious whether the 
case is a solitary one, or if in other species other types of gonophores, of those stated by Kiihn, 
might perhaps be found united in one and the same species. On that account I have (191 5) more 
closely examined the development of the gonophores of, among others, the Tnlmlaria indivisa Lin. 
and the Tnbularia rcgalis Boeck, two species in whicli a marked sexual dimorphism is found pro- 
nounced in the external characters of the gonophores. The examinations resulted in the startling result 
that the female gonophores of both species are eumedusoid, though not equally high in medusoid 
organisation, whereas the male gonophores of both specie^ are heteromedusoid and of entirely the 
same organisation and development as the gonophores of the genus Lampra Bonnevie (1898) (comp. 
Broch 1915). It is owing to the gonophores that Lampra is separated from Corymorpha, the latter 
genus producing free medusae or having gonophores eumedusoid. Acting on this principle of division, 
as far as the species of the genus Tjibtdaria are concerned, we should have to separate the male 
Tubularia indivisa and Tnbularia regalis as a new genus, while the female individuals belonging to 
the same .species would retain their places'. 

The outcome of the searching studies of the last years shows, indeed, that in proportion as a 
greater number of species have been examined, the more evidently the characters of the gonophores 
appear as criteria of species. The increasing knowledge of the gonophores makes ever clearer that 
the gonophores alone cannot form the base of any division of genera, but at most serve as second- 
arily corroborative. 

The free medusae show throughout a greater abundance of forms developed than the polyps, 
which are more conservative. No doubt, the medusce present a series of phenomena of adaptation 
and, accordingly, display several characters of convergency, to which the systematists are inclined to 
attach a greater phylogenetic value than is their virtual due. Nowhere, I dare say, the adaptations 
to habits of life and the accommodations to varying physical conditions play such a part as with the 
pelagic organisms, to which the slightest variation of salinity aud of temperature causes great 
changes of viscosity of the surrounding water, decisive of the adaptation of their suspension organ.s. 
Tlierefore, the hydroid systematist should not lay too much stress on the statements of the medusoid 
specialist as to the systematic grouping of the free-swimming generation; phylogenetically the char- 
acters of the nurse generation are of the greatest interest. A similar state of things urges itself with 
the sessile gonophores. It is a circumstance of vital importance to the maintaiuance of the species, 
that the generative individuals are able to accommodate themselves quickly to the peculiar conditions 
of life to which the species is subjected. What I observed in my treatise on the Stylastcridcr (1914), 
is fully applicable (or even more so) to the case under consideration: "Owing to their conservatism in 
development the polyps are of tlie most important phylogenetic interest. The gonophores, the genera- 
tive individuals, on the other hand, might almost be said to be a playball in the hands of chance 
biological conditions and thus phylogenetically have much less interest". 

' The possibility of a fusion of four species is precluded, as in 'ruhidnria hidhnsn find in 'J'lihularia rrgalis (J and 9 
occur in the same colony. 



HYDROIDA 



On account of their dependence on outward conditions and their power of plastic acconnnodation 
to biological influences, the gonophores are unsuitable for basis of division into genera. On the other 
hand, the genera, owing to the conditions of the gonophores, often fall into a series of biological 
groups (or subgenera). The systematists who lay the main stress on the gonophores in establishing 
the system, in fact apply biological conditions as fundamenlum divisionis, and let phylogenv, the pro- 
perly governing principle of systematic inquir\-, recede into the shade. 

b. The comparative anatomy of the nourishing individuals, and the system of the 

athecate hydroids. 

An exact review of the researches of the last years makes ever clearer, as also appears from 
the statements above, the correctness of Levin sen's view (1893), maintaining that in the great classifica- 
tion of the hydroids the main stress must be laid on the peculiar conditions of the nourishing polyps, 
and reducing at the same time the modifications of growth and the conditions of the gonophores as 
characters of subordinate importance. Later investigators' have, indeed, attached ever more importance 
to the conditions of the polyps. But in so doing they have almost exclusively taken into considera- 
tion such morphologic criteria as urge themselves on a superficial view of the polyps. The inner 
anatomy, on the contrary, has been disregarded. Kiihn (1913) certainly b\- the way points out that 
the inner anatomy can be different in the different groups. He treats (1. c. p. 50) at some length 
of the peculiar structure of the pol>ps of the TiibnlariidcB^ and points out the multifarious development 
of the tliecaphores. But in drawing the bases of his system he makes no attempt to turn these features 
to further account. 

As a result of searching inquiries, the structure of the polyps in the different genera and 
families has turned out not to be quite so homogeneous as it has been generally held. Both in the 
construction of the ectoderm and in that of the endoderm differentiations occur, which may be char- 
acteristic of greater or smaller groups of species and give us several holds for judging the systems 
drawn up for hydroids in the course of time. 

Therefore, it will here be appropriate to give a brief synopsis of the more important peculiarities 
of anatomy distinguishing the various groups of athecate hydroids, in order to apply them afterwards 
to drawing up the system of the group. 

The ectoderm, deciding by the disposition of its elements whether the tentacles have to be 
claviform or not, has, to some extent, been turned to account as fundamentum divisionis. The clavi- 
form .shape is particularly due to the accumulation of the stinging cells on the tips of the tentacles, 
while the tentacles are filiform when the nematocysts are more equably distributed. A third type of 
tentacles, which, as far as is known, is found with all thecaphore hydroids, occurs in the Eudcndriida; 

■ Works like that of Poche 11914) I leave out of account. That sort of "zoology" which is based not on study of 
the organisms themselves, but only ou what may be beaten up from books, here debouches in the construction of airy castles 
of compUcated systematics, which does not advance zoological science by a hairbreadth, but only contributes to increasing 
the systematic confusion. Between "regnum" and "family" are inserted 34 - thirty four - degrees. It is a matter of regret 
that we do not learn how many osculant categories must be placed between -family" and "indi^•idual" to give a "full" picture 
of nature. But this will suffice to illustrate the scientific value of the work. 



HYDROIDA 



here the stinging cells are arranged in dense transverse belts round the tentacles so as to give these, 
when distended, a peculiar transversely striped appearance. 

On the ground of filiform and claviform tentacles Kiihn (1913) divides the athecate hydroids 
into the two principal groups of Filifera and Capitata. However, we find in the latter group also 
instances of filiform tentacles; in W\^ Pennariida: ^Xxioxm. tentacles occur together with claviform ones; 
in the TubulariidcB, on the contrary, the claviform tentacles have disappeared, at any rate in the polyps 
fully developed. Kiihn (1. c. p. 228), therefore, also makes the reservation that the tentacles are "dauernd 
oder in der Jugend geknopft". Embryological studies on Corymorpha have, in fact, shown that the 
actinula has claviform tentacles (Torrey 1907, Hartlaub 1907). However, this state of things cannot 
be o-eneralized as a matter of course to embrace the Tubularja; on the contrary the figures of A 11m an 
(1872) show quite distinctly that the actinula in Tubularia larynx and Tubularia indwisa have filiform 
tentacles, and inquiries into the Tubularia rcgalis in the Trondhjem Fjord have shown no trace of 
capitate tentacles during the development of the actinula. Nor do here claviform tentacles occur in 
full-grown polyps. 

But even though the definition of Kiihn must be characterized as erroneous so far, there is 
another criterion .showing that his division of groups is correct. A searching study of the ver)- nemato- 
cysts, shows, as a matter of fact, that the athecate hydroids fall into two large principal groups, cor- 
responding to the Capitata and the Filifera stated by Kiihn. 

In the hydroids occur two characteristic principal forms of nematocysts (PI. I, figs 1—7). In all 
tlie Capitata we find large oviform or almost wholly spherical nematocysts of the same principal type 
as is often mentioned in the Hydra. These large nematocysts are always accumulated on the tips of 
the claviform tentacles, as in the Coryne^ while on the filiform tentacles of the Tubularia the)- are 
more equably distributed all over the ectoderm of the tentacles. However, these stinging capsules are 
also found elsewhere in the ectoderm of polyps, as is the case with Monocorync and Myriothcla. In 
the last mentioned form the nematocysts, like those oi Millepora, have developed dimorphicly; besides 
the typical oviform nematocysts we find here a larger and more slender oval form; in general the 
latter nematocysts are outnumbered by the oviform ones, but still they amount to a large percentage 
of the total stock of stinging capsules occurring in the animal. In the Millepora tliis type of nemato- 
cysts, judging from the figures in hand, is rather broad. 

The rest of the hydroids are distinguished by quite a different type of nematocysts. The pre- 
dominant type is a very small, all but rod-shaped nematocyst, particularly occurring in the tentacles, 
generally accumulated in belts, verticall)- on the tentacle axis, giving the tentacles, when wholly 
stretched out, a peculiar transversely striped appearance, like that of the tentacles of the Eudciidriuiii 
recorded. Concurrently with this typical small nematocyst distinguishing all Filifera sometimes occurs, 
finally, a somewhat larger form, as in the Eudendriuin and the Sfylasterida. In the Eudendri^im 
Wrighti we find in the tentacles only small rod-shaped stinging capsules; on the contrary in the 
basal whorl of stinging cells of the polyp body of the species in question the capsules are much larger, 
though keeping a slenderly oval appearance. It is strange that this large type of the F.udcndriuvi 
and the Stylasteridm should appear almost entirely consistent with the aberrant slenderly oval nemato- 
cyst with the Myriothela. The simultaneous occurrence of the type in so different and so highly 



HYDROIDA 



organised forms suggests, indeed, that we have before tis phenomena of convergency, the cause of 
which is at the moment quite inexplicable. 

However, not only the ectoderm itself and its elements are of interest to comparative anatoni\-. 
The derivates of the ectoderm are of great importance. In the same way as the ectoderm of 
the stem secretes a periderm, we find that with all tliecaphorc hydroids a chitinous hydrotheca is 
secerned by the ectoderm of the polyp. Remarkably enough, a parallel is found also in a single genus 
of the athecate hydroids, the Perigonimiis. In this genus the ectoderm of the polyp secretes a 
"ps end oh ydro theca", a hydrotheca-like, folding periderm case of a jellied substance surrounding the 
basal portion of the polyp up to the tentacle whorl. The first inquiries as to the pseudohydrotlieca 
have been made by Hadzi (1913 and 1914). The pseudohydrotheca is di.stinguished from the real 
hydrotheca in having no free margin, but being distally firmly connected with the ectoderm of the 
polyp so as to be indistinguishable, on a superficial view, when the polyp is wholly distended. On the 
contrary, when the polyp is contracted, the pseudohydrotlieca is, in general, easily discerned, forming 
a richly folded cover round the basal portion. The pseudohydrotheca bears some resemblance to the 
genuine hydrotheca by the way in which the polyp is attached to it, the supporting lammella of the 
pohp being basally connected with the pseudohydrotheca by a whorl of small chitinous pro- 
minences. Similar chitinous jirominences are also seen, for instance in Endendrmm, connecting the 
soft parts of the stem with the periderm cover; systematically, however, no particular interest can be 
attached to them. 

Also in the endoderm diversities of great interest are found. The .simplest, mo.st homogeneous 
shape is represented by the gastric endoderm of Cla7'a (Broch 1911), forming a homogeneous epithel- 
ium for absorbing the nourishment, from the orifice of the mouth to the passage of the polyp into 
the stem; almost all of the cells of the gastric endoderm are filled with larger or smaller grains 
showing a strong affinity to Delafi eld's haematoxyHne ("nutritive cells" and "albumen cells", comp. 
Schneider 1902). As to Coryur, the state of things is quite different; here the endoderm in the 
portion nearest to the mouth is extremely rich in mucous gland cells, while the digestive cells are 
comparatively few in number. In Coryiir we must consequently distinguish between the oral 
portion secerning mucus and the part of the endoderm of the polyp which is the proper gastric or 
digestive portion. The difference between these two endodernial zones appears still more distinctly in 
Myriotlula; the glandular cells are here densely concentrated on a small portion near to the mouth, 
strongly conspicuous by its clear blueing after being treated with Dela fie Id's haematoxyhne; the 
other endodermal cellular forms have almost wholly disappeared in the glandular zone with 
Myriothela. In Ttibularia, on the contrary, the glandular zone has disappeared, so that the endoderm 
here by its homogeneous appearance all over the polyp strongly recalls the case of Clava. 

A rather different state of things is found in the Bougainvilliidie. Here, indeed, mucous cells, 

occur in the oral endoderm of the polyp. But the bulk of the cellular elements in the oral portion as 

far as the whorl of the tentacles, is constituted by cells which appear indifferent to the nutritive elements. 

All the cells here have small nuclei strongly concentrated, while in the gastric endoderm taking the 

nourishment, from the whorl of tentacles and downwards, the nuclei are large, with open chroraatine 

net-work. This condition of things is still more pronounced in Endnidrium, the mucous cells of 

2 

The Ingolf-Expedilion. V. 6. 



jQ HYDROIDA 



which, however, are most frequently concentrated in the proboscis, closely to the basis of the tentacles, 
where the entrance to the proper gastric cave is found. 

Thus there is throughout a typical difference between the Capitata and the Filifcra as to 
endodermal matters, though the Clava apparently presents an intermediate form or a form of depar- 
ture from which the other types are derivable. Simultaneously the Filifcra, as far as can be judged 
from the data in hand, bear a typical resemblance to the thecaphore hydroids, and here the parallel 
between the Eudcndrinni and the Campanulariida; is particularly obvious. Whether this is owing to 
a closer affinity or it must be explained only as a phenomenon of convergency, we must at present 
leave unanswered, because of our deficient knowledge of the group. 

A single family, the Tuhdariidcp, shows an anatomic p.eculiarity, as with the species of this family 
there occurs a peculiar m'esogloeal formation. At the basis of the large tentacles the endoderm has 
developed a thick supporting cushion formed as a ring of mesogloeal tissue of large cells roiuid the polyp. 
This leans inwardly on the supporting lamella, and is bounded against the axial endoderm of the tentacles 
by a delicate membrane, which in .some cases it is rather difficult to point out. 

Hollow tentacles occur in two ways. In their original .shape they are, as is the case with 
Hydra, openly communicating with the gastric cave of the polyp. This state of things, however, 
has ceased with most hydroids and cannot be found in any of our northern species. In these, on the 
other hand, occasionally occurs, as in Clava muliicornis and in Myriotlicla a central cavity in 
the tentacles, at any rate in their basal part. This cavity, however, does not communicate with the 
gastric cave of the polyp, but is basally bounded by the unbroken supporting lamella. This central 
cavity of the tentacles, as it is represented by well-developed Clava viulticornis, might be looked upon 
as a primitive condition of things. However, in forms so highly organised as Myriothrla, it must 
sooner be considered as a secondary phenomenon, which cannot have an)- direct correspondence with 
the i)rimitive condition of things in Hydra. 

In Myriothela the tentacles show a peculiar structure, elsewhere unknown in the hydroids. 
The matter is more precisely described by Jaderholm (1905). The .supporting lamella is in the 
thickened distal part of the tentacle transformed into a cushion constructed by delicate radially 
placed fibres, showing no cellular structure and densely crowded. They seem to be intended for 
strongly stiffening the distal portion of the tentacles and for making the armed outmost portion of 
the tentacles larger and more powerful of resistance. 

On the ground of the anatomical features stated, and of morijhological characters hitherto turned 
to account in systematics, is brought about a system which, as far as the athecate hydroid families 
are concerned, can be summed uj) in the following key of determination: 

A. No formation of gonophores. Eggs and sperms, developed in the wall of the polyp. The tentacles 
— if such ones occur — hollow, openly communicating with the gastric cave (Sectio Simplicia nov.) 
Fam. Hydridm. 

B. The generative cells developed in special gonophores. 

I. The polyps with large, broadly oval or spherical nematocysts (Sectio Capitata Kiihn). 
a. The tentacles of the polyp wholly or in part claviform. 



HYDROIDA J J 



1) The polyp having only one kind of nematocysts. Tlie claviform tentacles of simple strnc- 
ture, having no central cavity and" no particnlarly developed supporting lamella. 

a. All tentacles claviform. Fam. Corynid(P. 

fi. The distal tentacles claviform; proximally a whorl of filiform tentacles. Fam. Poinariidw. 

2) The pohps, besides having oviform or spherical nematocysts, also provided with .slenderly 
oval or nearly cylindrical stinging capsules. 

a. Without calcareous skeleton. The claviform tentacles having a central cavity, greatly 

widened distally, but not openly communicating with the gastric cavity of the polyp. 

The supporting lamella, in the outer portion of the tentacles, developed into a thick 

radial fibrous supporting tissue. F^am. Myriolhrlida'. 
/?. Colonies with calcareous skeleton. The tentacles of simple structure, having no central 

cavit)-. Fam. Millcporidce. 
b. All the tentacles of the pohp filiform, arranged in two main circles: 

1) The proximal (basal) whorl of tentacles leaning against a well-developed mesoglocal cushion. 
The polyps of radial synnnetrical structure. Fam. Tnbulariida. 

2) The mesogkxal formation at the basis of the proximal whorl of tentacles almost wanting, 
owing to radial canals. The structure of the polyps bilaterally symmetric. Fam. Braitch- 
ioceriantliidcB. 

II. The nematocysts always only .slender, the small ones quite rod-shaped. (Sectio Filifera Kithn). 

a. Colonies without calcareous skeleton. 

1) The tentacles irregularly spread all over the polyp, or reducible to a single large tentacle. 
The endoderm not differentiated into oral endoderm and gastric endoderm. Fam. Clavidcc. 

2) The tentacles forming a main circle round the polyp. The endoderm differentiated into 
an oral endoderm and a gastric endoderm. 

a. The polyps fusiform with conically pointed proboscLs. Fam. BoHgainvilliidm. 

/9. The broad body of the polyp well defined from the stem, and provided with a clavi- 
form proboscis placed with a narrow basis on the whorl of the tentacle.s. Often two 
kinds of nematocysts, large ones and small ones. Fam. Eudcndriid(z. 

b. Colonies with calcareous skeleton and with two kinds of nematocysts, the large ones being 
slenderly oval or nearly cylindric, frequently slightly cur\-ed. Fam. Stylasterida. 



II. Athecate Hydroids of the Northern Atlantic. 

Section Capitata Kiihn. 
Family Corynidae. 

"Hydroids with fusiform or more cylindric polypes, whose oral portion is ct.; omted. 

The stinging capsules are large, oviform, or almost globular. All the tentacles of the polype are 
capitate with the stinging cells mainly concentrated on the thickened distal portion. The structure 



J2 HYDROIDA 



of the tentacles is simple, with no central cavity, and with a thin snpporting lamella without any 
particular thickening. In the endoderm we must distinguish between an oral portion, abounding 
in mucous gland cells, and the gastral portion proper. The colonies develop no calcareous skeleton". 

It is questionable, as is also pointed out by Kiihn (1913), whether it is justifiable to maintain 
the Corynidae and the Pa/i/ariidac as two distinct famihes. Stechow (1913) states that "das gleich- 
zeitige Vorkommen geknopfter und fadenformiger Tentakel ein vorztigliches Merknial fiir das Bestim- 
men ist"; simultaneously, however, he ranks the genera Acmilis and Clavatclla with the Corynidae^ 
though, having tentacles both capitate and filiform, they should, from this main characteristic, be 
reckoned among the Pennarndae. Also as compared with the Tuhulariidae, the limitation of the Pcnnarii- 
dac makes some difficulty. Thus Bonne vie (1899) e. g. classes Hcterostepliaiius among the Tu- 
bulariidac in spite of the fact that the species is provided with capitate distal tentacles. Stechow 
(1913), on the other hand, as well as Broch (1911), ranks this genus with the Pennarndae. I regret 
that I am in lack of material for a more thorough inquiry into the Pcnnariidae ; it is not unlikely 
that the anatomical structure of the jjolypes might afford safer holds for the judging of this group of 
hydroids than the merely outward morphological characters. 

The Corynidae form a very central group, with which all the other groups of the section of 
Capiiata, stated by Kiihn, are likely to have originated. — At the first glance it may appear as if 
one of the genera Monocorync has got uematocysts heterogeneously developed, so as to show, be- 
sides oviform or globular capsules, partly also long, narrowly oval ones. That this is not the case, is ascer- 
tained by a careful study of material of Monocorync gigantea (Bonne vie) collected in the 
Trondhjemsfjord. Partly all the nematocysts of this shape are discharged, and partly developmental 
stages of other nematocysts than oviform ones are not traceable. It is, therefore, obvious that, in 
being discharged, the oviform nematocysts assume a narrowly oval shape. The apparent dimorphism 
of the uematocysts would otherwise have been greatly interesting as a connecting link with Myrio- 
flicla^ and would have been likely to support the supposition of Bonne vie (1899) of the derivation of 
the last-mentioned genus from the Corynidae through Monocorync. But as a matter of fact, the large 
Monocorync gigatitea shows the anatomical structure of the true Corynidae. Swenauder (1903) mentions 
that its tentacles are coalesced at the basis; this statement, however, only holds good for the ectoderm, 
which in several places appears to be stratified; the endoderm, as far as the single tentacles are con- 
cerned, continues, wholly surrounded by the ectoderm, to the supporting lamella. Monocorync gigantea 
presents another peculiarity which the inquirers liave hitherto obviously failed to notice; the indivi- 
duals are hermaphrodite, in a nu)st peculiar way. Not only we find in a single individual sheer female 
and sheer male gonophores; but among these also occur several gonophores containing, besides large 
ova, also sperms and .spermatocytes of all stages. The gonophores of this species are reduced to 
cryptomedusoids. 

In tlie internal structure of the polype of the Corynidae our attention is fixed on a great ac- 
cumulation of mucous gland cells in the endoderm next to the orifice. Here are densely accumulated 
a lot of cells, whose affinity with Delafield's haematoxyline make them very consi^icuous on material 
well preserved. This concentrated glandular zone is found still more strongly marked in the Myrio- 



HVDROIDA J, 



thelidat\ whereas in the Tiibulariidar it has disappeared. It forms a striking contrast to the proboscis 
of the Eudc)idriidai\ the outer oral portion of which is more abounding in indifferent endodermal 
cells and more nearly approaching the state of things in the BougainviUiida(\ in which, however, also 
the indifferent endodermal cells appear in larger numbers. As is mentioned before, tliis oral zone is 
wanting both in the Clavidac and the Stylastcridac. 

The Coryiiidae, like their near relations the AlyriothcUdae^ are distinguished by a vigorously 
developed polype musculation, and in connection with this show an astonishing power of changing 
appearance and volume. It is easy for them to swallow a comparatively large copepode, and in my 
material I have found several shapeless-looking C^ryw^-polypes which were digesting rather large 
crustaceans. Thus they are very greedy animals, frequently feeding on organisms larger than the 
polype of normal size. Series of sections show how the food half dissolved also is led direct into the 
gonophores and is absorbed by their endodermal spadix. The endodermal cells of the spadix then are 
filled w-ith some granulous contents, which are greedily absorbing and tenaciou.sly keeping the haema- 
toxyline of Delafield, while they are rather indifferent to both the haematoxyline of Bohmer and 
to eosine. However, the cells also contain several eosinophile grains. 

Gen. Coryne Gaertner. 

^'•Corynidac forming colonies, with solitary capitate tentacles spread all over the hydrauth. The 
colony is formed by the ramification of an upright hydrocaulu.s, whose tubes do not communicate 
through secondary canals. The gonophores are developed on the proximal portion of the polypes". 

Many investigators place the species productive of medusae in a separate genus, Syticoryne. 
This criterion, however, is of merely biological nature, and thus of less importance to systematists. 
And apart from this, it is evident that some species of Coryitc produce more strongly reduced eume- 
dusoids which are only quite exceptionally detached from the mother colony. The species have not 
yet been sufficiently examined. Therefore, it is obvious that, for instance, the species Coryne Lovcni 
(M. Sars) must have been several times confounded with Coryne Sarsi (Loven). In the medusoid 
gonophores of the former species the tentacles are wholly reduced, while Coryne Sarsi has complete 
medusoid gonophores with tentacles. The opinion maintained by L. Agassiz (iS6o) and Hincks 
(1868), based on the observations of L. Agassiz (I.e.) and Clark (1865), that some species of Coryne 
at one time of their lives produce free-swimming medusae, at other times, ou the contrary, sessile 
eumedusoids, has not yet been refuted, but, quite the contrary, been strengthened by the observation 
of a parallel condition of things in species of Caiiipaiiiilaria (Giard 1899, Beliner 1914). It is 
not impossible that Coryne Sarsi should be one of these species of Coryne. In Cory)ie Loveni the 
eumedusoid gonophore has lost its tentacles, and at the same time the development of the generative 
cells shows us that the gonophores are not here normally disengaged from the colon)-. Other species, 
such as Coryne Hincksi Bonne vie and Coryne brevicornis Bonne vie, seem to have gonophores 
somewhat more reduced, still, however, keeping the medusoid structure strongly defined. These 
species, then, exhibit stages forming the transition to Coryne pusilla Gartner with its strongly 
reduced styloid gonophores. 



^. HYDROIDA 



If we, therefore, like Kiihn (1913) and Stechow (1913), separate Syncoryne as a genus of its 
own, there will be insurmountable difficulties about drawing the limits. If, as is done by Stechow, 
the limit is drawn by the production of free-swimming medusae, Coryne Loveni must normally be 
omitted from the genus Syncoryne, and a species such as Coryne Sarsi will probably have to be reck- 
oned sometimes among the Syncoryne, at other times, on the contrary, among the Coryne. If, on 
the other hand, we follow Kixhii and draw the limits of genera between species with eumedusoid 
gonophores and species having gonophores more strongly reduced, it may be greatly questionable 
where, for instance, Coryne Hincksi and Coryne brevicornis ought in fact to be placed. In this case 
as in others, the more species we learn to know more exactly, the more impossible it proves to draw 
the limits of genera on the ground of gonophoral conditions. To this must be added that in all the 
species of Coryne or Syncoryne the colonies and the polypes are so uniform as to their appearance, 
that the)- cannot with certainty be identified to species or included under one or the other of the two 
"genera", if the gonophores are wanting or only little developed. It is, therefore, absurd to insist on 
drawing an artificial and arbitrary line of distinction, founding on merely biological phenomena of 
adaption. 

Coryne Sarsii (lyoven) Johnston. 
1835 Syncoryna Sarsii, Lovcn, Bidrag til Kannedomeu af »Slagterna Caiiipannlaria och Syncoryiia 

p. 275, pi. 8, fig. 1—6. 
1847 Coryne Sarsii, Johnston. A History of the British Zoophytes, p. 43. 
?it)ii Syncoryne Sarsii, Ssemundsson, Bidrag til Kundskaben om de islandske Hydroider II, p. 72. 

"The delicately constructed colonies attain to a height of up to 30 mm. The hydrocaulns is 
wholly irregularly ramified with no distinct main stem; the branches form acute angles with the stem 
or the main branch whence they proceed; both the stems and the branches are almost entirely 
smooth with no rings nor wrinkles. The strongly contractile polype, when extended, attains to a 
length of up to 1.5 mm., and is then almost wholly filiform; when contracted, it is oviform or nearly 
globular. The numerous capitate tentacles are irregularly distributed over the polype. 

The gonophores develop into medusae, which are likely to break away during the greater 
part of the generative period of the polype; the medusa bud developes four tentacles. One or two, 
more rarely three, gonophores occur simultaneously on the polype". 

Material : 

Iceland, Reykjavik. Shallow water (as.sociated with small Mytilus). 

In all probability, Sa^mundsson (1902, 1911) is right in including these very delicately con- 
structed colonies under Coryne Sarsii. The occurrence of the species is boreal. But the possibility that 
the species is frequently confused with forms nearly related, as yet precludes certain decision as to its 
distribution. Coryne Sarsii is recorded from the coasts of Norway, Bohuslan, Denmark, Helgoland, 
Great Britain, Iceland, and Northern France. Har tlaub (1905 a) and Jad erhohii (1903), though with 
some doubt, refer some colonies from Tierra del Fuego and from Patagonia to the same sjjecies. 



HYDROIDA 



15 



Coryne Loveni (M. Sars) Boimevie. 
1835 Syncoryna ramosa, Loven, Bidrag til Kannedomeii af Slagterna Campanula n'a och Syncoryiia, p. 

275. Pl- 8, figs. 7-10. 
1846 — Loveni, M. Sars, Fauna littoralis Norvegiac, j). 2, footnote. 

1899 Coryne Loveni, Bonnevie, Norske Nordhavs-Expedition, ]x 14. 

"The colonies are rather coarsely constructed and attain a height of up to 30 mm. The hydro- 
caulus is wholly irregularly ramified and shows no distinct main stem. The branches proceed almost 
rectangularly from the stem or the mother branch, but at once curve upwards, forming a very acute 
angle or even a parallel with it. The hydrocaulus and the branches are almost entirely smooth, having 
only here and there wrinkles slightly indicated. The strongly contractile polype, when extended, 




200 m. _.__ 6ooni ._. ..jooom. ._ ^.. 2 ooo m. 

Text-fig A. The occurence of Coryne Loveni in the Northern Atlantic (the hatched coastal Region denotes 
a scattered occurence, the totally black parts indicate a connnon occurence) 

attains to a length of nearl}- 2 mm., a-.ul then is .slenderly fusiform or nearly cylindric; when contracted 
it is oviform, oval, or almost globular. The numerous capitate tentacles are irregularly distributed 
all over the polype. 

The gonophores develop into eumedusoids, 1.5 mm. long, with no tentacles, normally not break- 
ing away; they have four well-developed radial canals and a circular canal. Up to three gonophores 
occur on the polype near its base". 



Material : 

Greenland, Godthaab 
Norway, Bjarkoi, Lofoten 



literal (on Ascophylluvi) 
litoral (on Fncoidcae) 



l6 HYDROIDA 



Hartlaub (1907) informs tis that in his aquaria he has observed a Syncoryne, whose gono- 
phores are not set free, though being full-grown medusae with four tentacles well developed; the 
generative products are developed in the sessile medusa, which is reduced after having performed her 
generative task. Hartlaub refers this form to Corynr [Syncoryiic) Lovcni M. Sars. This identifica- 
tion however, cannot be right; most likely we have here rather in hand individuals of the Coryne 
Sarsii during the part of the generative period when the medusae are not detached. Through Mr. 
C. Dons, conservator at Tromso, I received a very copious material of Coryiie Loveni from Bjarkoi, 
where the species occurs in abundance on the Fucoidca in the tidal water region. The large number 
of individuals examined have most frequently two, more rarely three gonophores, which are developed 
into a complete medusa without any tentacles. The four -radial canals end in a small enlargement, 
which is the only indication of tentacles traceable. The species, accordingly, cannot be identical with 
the form recorded by Hartlaub, but agrees very well with the description and the illustration given 
by 1,0 v en. 

Coryne Lmieni \s earlier known only from the west coast of Scandinavia'. Jaderholm (1909, 
taf. I, fig. 7) gives an excellent drawing of the species collected from Bohuslan ; elsewhere it is recorded 
from the coast of Norway from Bergen as far as Lofoten, where its occurrence in the northern part 
of its habitat is most numerous. Some colonies from Godthaab show us that Cory 11 c Lovcni must 
also be added to the fauna of (Treenland. The species is native to the boreal tidal water zone and 
attains to its most luxuriant development in the passage to the regions of the Artie Ocean. 

Coryne pusilla Gartner. 
1774 Corynr pusilla^ Gartner, in Pallas: Spicilegia zoologica vol. i, fasc. 10, pag. 40; pi. 4, fig. 8. 
1893 Syncoryne vnrabilis L,evinsen, Meduser, Ctenophorer og Hydroider fra Gronlands Vestkyst, p. 150. 
1902 Coryne vervncnlaris, C/ruticosa, Syncoryne cximm, Ssemundsson, Bidrag til Kundskaben om de 

islandske Hydroider, p. 50. 

"The colonies are coarsely constructed, attaining a heigh. t of up to 40 mm. The hydrocaulus 
is wlioll)- irregularly branched, showing no distinct main stem; the irregularly curved branches are 
everywhere densely wrinkled and form almost right angles with the hydrocaulus or with the 
mother branch. The strongly contractile polyp, when extended, attains to a length of 2.5 nnn., and 
is then slender and narrowly fusiform or almost wholly cylindrical; when contracted, it is oviform or 
oval. The numerous ca]Mtate tentacles are irregularly distributed over the polyp. 

Tlic gonophores are globose, showing a st\loid structure. There occur 4—8 gonophores, irregu- 
laris- distributed over the proximal (basal) half of the polyp". 

Material: 

The Faroe Island.s. 

Iceland: Grindavik. On littoral algae (labelled Coryne pusilla and C. frulicosa). 

Reykjavik. On littoral algae (labelled Syncoryne exiniia and Coryne verniiciil(iris). 
Greenland (labelled Syncoryne mirahilis). 

' Dr. P. L. Kraiiip kindly informs nie, that Coryne Lor,- ni is abiinilant in the Little Belt. 



HYDROIDA 



A closer investigation of the living polyps and of their conditions very soon shows us that the 
appearance of the polyp is varying very strongly according to its state of contraction. Now it is 
stretched at length, assuming approximately the shape of a thin worm, now it is again contracted to 
a short, thick lump, very nearh- approaching the globular shape. Sometimes the polyp is at the widest 
at the base; sometimes it is contracted in this jxirt, .so that the largest width appears farther out 
The study of the live polyps thus, in this case as in many other.s, shows us that many characters 
which have been turned to account as criteria of species with the Coelentcrata, may be of most doubt- 
ful value or even of no importance whatever to classification. In the first place, of course, this is appli- 
cable to the various states of contraction, which, in Corync pitsiUa^ have even led to subdivi.sion into 
several species. Jaderholm (1909) thus, on account of difference of .shape of the polyp, still 
distinguishes Coryitc piisilla and Coryiic vrriiiiculan's Hincks; as, however, all other characters wholly 




-_ 1000 Tl. 



Text-fig. B. Tlie distribution of Coryii,: piisilla in Uie Northern .Atlantic. 

agree, and the differences put to account as specific characters fall far within the limits of the polyp 
movements described above from observation of living individuals, the separation into species cannot 
be recognized; Coryne vcr)iiicnlaris forms a synonym of Corync pusilla and, in fact, only represents a 
phase of the movement of the polyps. 

Corync piisilla has previously been recorded from the north of France, from Great Britain and 
Ireland, from Helgoland, from Denmark, from Bohuslan, from the west coast of Norway, from the 
Faroe Islands, and from Iceland (Reykjavik). In m>' material there also occurs a colony marked 
"Greenland?", wrongly determined as Syncorync mtrabilis Agass; the species thus seems to belong to 
the fauna of Greenland, but particulars are still missing. The rather numerous Icelandic colonies of 
the species are all derived from the south-western point of the island. The species, accordingly, must 

T.,e,„go.f.E,peaUIo„.V.,. ^ 



HYDROIDA 



be characterized as southern boreal; it mainly occurs along the coasts of the North vSea and round 
the British Isles; how far it advances to the north on the coast of Norway, we do not as yet know 
with certainty; but a any rate it does not push forward as far as into the Arctic seas. 

Coryne sp. aff. Hincksi Bonnevie. 

Material : 

"Ingolf" vSt. 44. 61^42' Lat. N., 9°36' Long. W., 545 met. 4.8°. 

A small colony of young individuals of a species of Coryne is attached to the stalk of a Tn- 
bularia sp. The hydrocaulus is irregularly wrinkled and attains a height of up to 6 mm. with polyps 
1—2 mm. long. There occur 4—8 small, apparently meduso'd, gouophores at the base of the polyp 
closely below the tentacles. The tentacles are short. The stolon of the colony is reptant, the stalks 
of the polyp are unbranched. On account of the bad state of preservation it is impossible to furnish 
a proper design of the individuals. 

It is possible that the individuals belong to the .species Coryne Hincksi Bonnevie, which 
has previously been recorded only from a depth of 100 fathoms near Hammerfest (Bonnevie 1899). 



Family Myriothelidae. 

"Large solitary hydroid polyps with stratified ectoderm, in which occur two kinds of nemato- 
cysts. Besides the typical oviform nematocysts of Capitata are found in somewhat smaller numbers 
uarrowly oval or nearly cylindrical, rather large nematocysts which are especially frequently occur- 
ring in the ectoderm of the gonophores. The tentacles are capitate with a central cavity which does 
not communicate with the gastral cavity of the polyp, and which is distally broader. The vigorously 
developed distal portion of the tentacles is shored up by a particularly developed portion of the supp- 
orting lamella, here showing a fibrillary structure with fibres radiarily arranged. The supporting 
lamella is vigorously developed in the wall of the polyj) and provided with bilamellae. The endoderm 
exhibits a dense circle of mucous glands at the mouth of the animal. No calcareous skeleton is 
developed". 

The Myriothelidae seem to be nearly related to the Corynidae^ and also to the Milleporidae^ 
which latter form calcareous skeletons. The last mentioned family presents in its dimorphically 
developed nematocysts a strong resemblance to the Myriollielidac. However, only a character as the 
peculiarly developed supporting lamella in the thickened distal portion of the tentacles, as well as 
the dimorphic development of the nematocysts, justifies the distinction of the Myriothelidae as a parti- 
cular family beside the Corynidae. Already Bonnevie (1899) has pointed out the near rela- 
tion between Myriothelidae and Corynidae and the bridge between them suggested by the species Mo- 
nocoryne gigantea (Bonnevie). The arrangement by groups of the tentacles and the attachment of 
the gonophores to these groups are very likely to form the base of the development of the blasto- 
styles of Myriothcla. But on account of the peculiar direction in which the structure of the tentacles 



HYDROIDA j„ 



of the Myriothclidac has developed, we cannot subscribe to tlie view of Kiihn (1913), reducing the two 
families into one. The anatomical structure of the iDol\ps of the two groups differs too mucli, and to 
this difference must be attached a greater importance than the investigators have hitherto been inclined 
to do; anatomically the difference between the groups is too great to allow their amalgamation, in 
spite of the agreement of the two families as to the eudoderuud nnicous gland portion near the ori- 
fice of the polyp. 

Hitherto only one genus has been recorded of Myriothelidac. 

Gen. Myriothela M. Sars. 

''The large solitary polyps have only exceptionally slight indications of hydrocaulus; in general 
the base of the pol)"p is truncate or pointed and pro\-ided with rliizoids or filaments of adhesion, 
which are in fact transformed tentacles. Both the ectoderm and the endoderni are stratified. The 
tentacles are capitate and are irregularly distributed over the pohp and the blastostyles. The gono- 
phores are developed on small polyp-like blastostyles attached to the inferior half of the polyp; the 
blastostyles bear tentacles on their distal portion". 

The genus Myriothela is recorded from the northern seas and from the Antarctic Ocean. The 
spread and rare occurrence of the individuals prevents us from deciding whether the genus is in fact 
bipolar, as the finds hitherto recorded seem to indicate. 

Myriothela phrygia (Fabriciu.s) M. vSar.s. 
1780 L2tccrnaria phrygia Fabricius, Fauna Groenlandica, Nr. 333, p. 343. 
1851 Myriothela ardica M. Sars, Beretuing om en zoologisk Reise, p. 134. 
1873 — phrygia G. O. Sars, Bidrag til Kundskab om Norges Hydroider, \^. 130. 

"The capitate or almost cylindrical polyp extended reaches a length of about 400 nun. The 
inferior termination of the polyp is truncate, and it is attached to the substratum by tentacle-like fila- 
ments of adhesion. Above the portion wearing blastostyles it is studded with strong capitate tentacles; 
on the other hand tentacles are wanting on the surface of the polyp between the blastostyles. 

The cryptomedusoid gonophores are developed on small polyp-like blastostyles, attached to the 
inferior portion of the polyp and wearing capitate tentacles on their outward parts. The female blasto- 
style has only one or two fully-developed gonophores at the .same time, while the male blastostyles 
wear numerous gonophores". 

Material: 

"Ingolf St. 117. 69''i3'N., 8°23' W., depth 1003 fathoms, ^ 1° C. 

— St. 125. 68°o8' N., i6^"o8' W., — 729 — -^ 0.8° C. 

Myriothela phrygia has an enormous faculty for extension and contraction, and it is likely to 

share this faculty with its nearest relatives. A specimen I had the opportunity of observing when it 

was brought up by the trawl in the Trondhjemfjord, had stretched its distal portion wearing tentacles 

so stronglv that the animal was as thin as a thread and measured up to 30 cm. in length; but as 

3* 



20 



HYDROIDA 



soon as it was irritated by the preservation fluid, it contracted to a length of only 9 cm., and sinuiltan- 
onsly the diameter of the distal portion of the polyp increased to the measure of 2-3 mm. This 
observation shows how little importance is, in fact, to be attached to the absolute measures of the 
polyp in the limitation of the species of Myriothela. While the individuals from st. 117 wholly agree 
with the earlier descriptions and drawings of the species, the defective specimen from st. 125 (tab. I, 
fig. 8) at the first glance differs greatly. The broad, longitudinally strongly contracted basal portion 
is studded with blastostyles in a narrow belt, above which the polyp tapers rapidly so as to assume 
a conical appearance fairly reminding of the drawing by Bonne vie of Myriothela mitra (1899, tab. IV, 
fig. 3). However, a closer examination shows that the distal portion of the polyp has been torn off. 




Text-fig. C. Localities of Myriothela phrygia in the Nortliern Atlantic. 



and as its trunk above the blastostyles is studded with capitate tentacles, while the polyps of the 
species mentioned have no tentacles at all, a mistake of identity is out of the question. 

Myriothela phrygia is an arctic deep-sea form, mainly occurring in the icy water at the bottom 
of the northern seas. It is recorded from Taimyr (Jaderholm 1908), from the north of Norway, and 
from tlie depths of the ocean between Spitzbergen and Greenland (Bonne vie 1899), besides from the 
localities laid down in the map subjoined (Text-fig. C). The original description has been given on 
specimens from Greenland, from where, however, we still lack particulars as to localities. "Ingolf 
now adds two new finds in the waters of the Arctic Sea between Iceland and Jan Mayen. On the 
whole, the occurrence of the species is scattered; most of the finds are situated in high-arctic regions, 
and here the species is .seen to occur even at so small a depth as between 12.8 and 14.6 m (Jader- 
holm igo8). Therefore, two localities are, indeed, apt to give surprise. One of these localities is recorded 



HYDROIDA 2 J 



from the "Michael Sars" 1902, when the species was fomid in the warm Atlantic waters to the south of the 
Wyville-Thomson-Ridge (Brocli 1903). There is in this case a possibility that the animal has been carried 
with Arctic currents from northern regions; if so, the currents have conveyed the animal at an earlv 
period of life to the new locality, where it has been able to subsist and develop further. The other 
localit)-, in the Trondhj em fjord was previously recorded, and the Trondhjem Museum was in possession 
of a defective specimen which was said to have been taken in the fjord ; but jiarticulars were wanting 
till the researches of the fjord in 191 1 brought to light, from the depth of 200 m., near Tautra, and 
thus in the midst of the Atlantic water layers of the fjord, a well developed female polyp. This find 
gives the more surprise, because there is left no opening for the possibility that the specimen should 
have been carried to this place from Arctic water layers. Like other Arctic hydroids, such as 
Tnbularia rcgalis Boeck, Coryntorpha grociilaiulica (All man), and Stegopoma pHcatilc (G. O. Sars), 
Myriotlicla phrygia thus thrives very well in the region of the Trondhjemfjord which is otherwise 
characterized by Atlantic Lophokelm-x&eia. This cannot, however, be turned to account as a proof 
against the Arctic character of the species; in the Trondhjemfjord all these si^ecies must be looked 
on as Arctic relicts. 

Family Tubulariidae. 

"H\droids forming colonies, or solitary, with large oviform or globose nematocysts in the ecto- 
derm. The tentacles of the full-grown polyp are filiform and simply constructed with no central cavity; 
they are arranged in two main circles, a proximal whorl round the broad basal portion of the polyp 
and a distal whorl round the mouth. The basal whorl of tentacles is sujjported by a ring-shaped 
mesogloeal cushion round the basal portion of the polyp. The polyps are radially symmetrical. The 
supporting lamella shows a very simple structure". 

Most authors refer to this family also Brancliioccriaijtlius^ which I reckon as the type of a family 
of its own, the Branchiocerianfhidac. This family is distinguished from the Tubulariidae partly by bilateralh- 
symmetrical polyps, partly by the peculiar anatomical structure of the polyps. In fact, the structure of the 
polyps of the Branchioccriauthidac differs greatly from that of all other hydroids (comp. Stecho w 1909). 
There occurs a supporting lamella of complicated structure, and the polyp is provided with numerou.s, 
prominent radial canals. They are distinguished from the Tubulariidae also in their inner anatomy by almost 
lacking any trace of mesogloeal tissue at the base of the proximal whorl of tentacles, owing to the 
radial canals. These points of difference are, indeed, of such importance that they fully justify the sepa- 
ration of Branchioccrianthzts into a family of its own, the Branchioterianthidac beside the Tubulariidae. 

Kulni (1913) divides the Tubulariidae into two subfamilies, Tubtdariinae and Coryviorp/iinae. 
The former he defines by the characters "Koloniebildend, Periderm gut entwickelt", while the latter 
is defined as "Solitar, Periderm hautig oder riickgebildet, Wurzelhaare". To this is to be observed that 
a species as Tubularia cornucopia Bonne vie is a typical Tubularia in spite of its forming no colonies. 
The filamentary appendages of Coryinorpha must be compared with similar phenomena in Myrwf/ie/a, 
some species of which have rhizoids, while others such as Myriotlicla Cocksi (Vigurs), attach thems- 
elves by a plateformed perisarc; when this is considered as nothing else or no more than a criterion 



22 HYDROIDA 



of species with Myriofhcla, there tells indeed little in favour of raising it to a distinguishing mark 
between two subfamilies of the Tulmlariidac. As far as finally the development of the periderm is 
concerned, this is a gradual character showing many transitions, to which no importance can be 
attached as a distinguishing mark between two subfamilies. 

Gen. Tubularia Linne. 

"Hydroids most frequently forming colonies, the hydrocaulus being surrounded by a stiff and 
chitinous perisarc. The polyps are radially symmetrical, having two main circles of tentacles, a proximal 
(basal) whorl of long tentacles leaning on a mesogloeal ring in the trunk of the polyp, and a distal 
whorl with short tentacles round the mouth. The tentacles are also in the actinula filiform.' The gono- 
phores are generally borne on blastostyles; the gonangia spring from the trunk of the polyp between 
the two whorls of the tentacles". 

The gonophores are, in this genus as in most other genera, sometimes medusoid, sometimes 
more or less reduced. The species producing free medusae have been grouped by many authors as a 
genus of their own, Hybocodon. In this case as in others, the question then arises where the line is to 
be drawn. While in species as Tubularia pulchcr (Sa^mundsson) the medusa breaks away, the fully 
developed medusoid gouophore in Tubularia rcgalis Boeck, as far as is known to us, never voluntar- 
ily relinquishes its sessile existence. If we follow Kiihn (1913), as might seem right, we get into a 
dilemma, having to refer the female of Tubularia regalis to Hybocodon^ while the male, having crypto- 
medusoid gonophores (Broch 1915), must remain in the genus Tubularia. Only this should be suffi- 
cient to .show the error of turning the organisation of the gonophores to account as fundamentum 
divisionis. No doubt, it is wrong to set up Hybocodon as a particular genus of hydroids, and the same 
is certainly the case with the genus Aiiliscns set up by Ssemundsson (1899), the medusae of which 
as we are going to see, are scarcely particularly distinguished as compared to the other Hybocodoii- 
medusae. 

Tubularia pulcher (Sa-Muundsson). 
1899 AkHscus fulclirr Stem unds son, Zoologiske Meddelelser fra Island, p. 425, Tab. IV. 

"Colonies, the hydrocauli of which are up to 50 mm. long, unbranched, and separated down to 
the rcptant hydrorhiza. The stalk is covered with a brown perisarc, which is thick at the liase, but 
upwards against the polyp narrowing periodically and at distinct intervals, so that the stalk gets an 
appearance approximately articulate; the spaces between the transverse striae, brought about in this 
way, attain their greatest length in the middle part of the stalk, being here 13 mm. long. The upper 
portion of the stalk is provided with a thin perisarc, widening funnel-shapedly into a thin collar 
under the polyp. The polyp is fitted out with a basal circle of 24 — 30 tentacles, about 5 mm. long; 
the distal tentacles, about 30, are placed, densely crowded, in a narrow belt, consisting of several rows, 
round the orifice, and attain a length of a little more than i mm. 

The gonophores develo]) into free Ilybocodon-meAwi^a.^ with gemmation on the bulb of the 

' Tlie tentacles of the actinula may be swollen at their tips (coiiip. All man 1872) but never show the dense accumula- 
tion of stinging cells here, which is so characteristic in the truly capitate tentacles of the section Capitata. 



HYDROIDA 2-1 



large tentacle; there are four radial canals. The hell exhiljits five exumbrellary stinging cell stripes. 
The gonophores are developed on eight blastostyles faintly branched, a little more than i mm. long". 

Material : 

Iceland, Reykjavik. Near the shore (i specimen). 

The specimen in hand is one of the original .specimens investigated by Scemnndsson (1899). 
It is an individual with hydrocaulus 30 mm. high. The polyp is fitted out with 25 proximal tentacles, 
5 nun. long, and 8 blastostyles a little branched, about i mm. long. A clo.scr inquiry of the gonophores 
gives a picture somewhat different from that drawn from the explanation of Scemundsson. In the 
first place the umbrella of the medusa is not quite symmetrical, but somewhat oblique, as in Ilyboco- 
lioii prolifcr L,. Agassiz. At first only one tentacle, not two, is developed on the large tentacle bull) 
(Tab. II, fig. 16); the "corpora acuminata et duo ovata", mentioned by Sccmundsson as springing 
from the tentacle bulb, are all gems of medusae; none of them can be made out as "initiuni tentacu- 
lorum novorum" belonging to the original medusa. Wherever at the first glance two tentacles seem 
to occur on the bulb, a closer research will show that one of them in fact belongs to the bud of a 
new medusa on the bulb of the gonophore. Therefore, we have to concur in the opinion of H art- 
la ul:) (1907) and subscribe to his explanation of the apparent occurrence of two tentacles with Hybo- 
codoii prolifcr as satisfactory for the species in hand, that "bei der Knospung von Hybocodon der Ten- 
takel in der Entwickelung stark voraneilt und schon fertig sein kann, weun der dazu gehorige JMe- 
dusenkorper noch nicht deutlich in die Erscheinung getreten ist". 

The conditions of gonophores described show a much nearer relationship to Tubidaria [Hybo- 
codon) Christinac Hartlaub {= Tubidaria prolifcr Bonnevie 1899). Hartlaub's drawing of Hybo- 
codon Christinac (1907, fig. 98) is, according to the statements cited, easil)- reconcilable to the figure a 
little more skeletonlike given by S:tmundsson (1899, tab. IV, fig. 3). Nor is the difference between 
the polyps very great; Bonnevie (1899) states for her specimen 14 proximal tentacles, about 10 mm. 
long, while the species stated by Sicmundsson is said to have 24—30. It is a matter of regret that 
we only know the length of the proximal tentacles of the specimen in hand. But on account of the 
great contractility of the tentacles, no particular systematical importance can be attached to their 
length, and as far as the difference of numbers of the proximal tentacles is concerned, we see in other 
Tubulariidac within easy reach such a variety that the difference quoted by itself cannot justify any se- 
paration of species. When Tubidaria Cliristiuac is nevertheless maintained as a separate species beside 
Tubidaria pulchcr, it is in the first place owing to the exj^ress declaration of Bonnevie (1899) that 
her specimen has no collar under the hydranth ; such a collar is, on the other liand,'strongly developed 
in Tubidaria pulchcr, though at the first glance it may seem very little distinctive on material preserved.' 

Hartlaub (1907) holds that the medusa is identical with the medusa drawn by Steenstrup 
(1842), Corync frilillaria, and much is speaking in favour of the correctness of this supposition. On the 
other hand, the polyp described by Steenstrup, in the same place and by the same name, cannot 
be identified. It may be that it really is a Coryuc; some features are even suggestive of Corync Lo- 
vcni M. Sars; but the only thing the drawing shows us with full certainty, is that the polyp is no 

' The original specimen of Boiinevies Tubidaria prohfer wa.s wanting in the museum of the Kristiania university. 



24 HYDROIDA 



Tubiilaria^ and that its niedusoid gonopliores, if they are rightly perceived, cannot develop into medusae 
of the Hybocodoii type. 

The only locality from which Tiihiilaria pulclicr is recorded with certainty, is the shore near 
Reykjavik, Iceland, where it has been found only once. 

Tubularia indivisa Linne. 
1758 Tubularia indivisa Linne, Systema Naturae, Kd. 10, p. 803. 
1899 — obliqua -\- T. indivisa Bonne vie, Norske Nordhavs-Expedition, p. 24. 

"Colonies, whose long dark brown-coloured hydrocauli are, in the lower part, twisted together. 
The stems are covered with a vigorous perisarc, but show no rings nor wrinkles. No collar is formed 
below the polyp. The polyp has a basal whorl of 20 to 30 tentacles up to 20 mm. long; the distal 
tentacles are up to 3 mm. long and densely crowded round the orifice in a whorl consisting of 
several rows. 

The female gonophores are eumedusoid with four rudimentary radial canals, one of which 
(the shortest) is often slightly indicated even in the gouopliore fully developed. The gonophore 
has, near the apex, a tentacle-like bulging, obliquely situated. The male gonophores are crypto- 
medusoid and almost wholly globular, not oval. The gonophores are born upon ujd to 10 blasto- 
stylcs, which attain a length of 10 mm. The actiuula-larvae, when set free, wear filiform 
tentacles". 

Material : 

"lugolf" vSt. 31, 66°35'N., 55^54' W.; depth 88 metres 1,6° C. (Davis's Straits). 

— St. 87, 65°o2'. N., 23°56'2W.; depth no metres (West-Iceland). 
Greenland: Davis's Strait (without further data). 

— Egede's Minde ( — — — ). 

Iceland: Brede Bngt 65°i2'N., 23°28' W., depth 36 fathoms. 

— Grindavik littoral. 

— Skagestrand depth 60 fathoms. 

— Vestmanno littoral. 

The Faroe Islands (without further data). 

The North Sea: the West side of large Fi.shing bank 57°7' N., 2°4o' E., depth i^] fathoms. 

Swenander (1903) has pointed out Mw^l Tubularia obliqua Bonn e vie (1899) is based on female 
individuals of Tubularia indivisa; thus in the very external characters of the gonophores this species 
presents a peculiar sexual dimorphism, and inquiries into the conditions of the gonophores (Broch 
1915) have made good that this sexual dimorphism is a radical one, the female gonophores being 
eumedusoid, the male ones on the contrary cryptomedusoid. — Tubularia indivisa is very easily con- 
founded with the following species, Tubularia rcgalis, particularly when only male individuals are in 
hand for examination. In this case only the somewhat different shape of the gonophores makes it 
possible to refer with certainty the individuals to one species or the other, the male gonophore of 



HYDROIDA 



25 



Tubularia itidivisa being globular, and accordingly broadh' roxindcd in the distal part, while that of 
Tubularia regalis is oval and showing an attempt to be pointed in the distal part 

Tubularia indknsa has a very wide distribution. Its main occurrence in the boreal seas is bound 
to the middle and deeper parts of the littoral region and to the upper part of the deep sea region. 
From the cold area we find the species but once recorded, by ('. rieg (1914). After the examination 
of his specimens I cannot confirm this record; the specimens consisting only of hydrocauli without 
polyps, more probably belong to another species of Tubularia inhabitiug the deep sea. 

To judge from literature, Tubularia iudivisa penetrates rather far into the shallower parts of 
the Arctic regions, where it is recorded even from the New Siberia Islands (Jiiderholm 1908). How- 
ever, as appears from what is stated above, there is a possibility that some of the Arctic individuals 




Text-fig. D. The distribution of Tubularia indivisa in the Northern Atlantic. 

are in fact to be referred to Tubularia regalis. — The species also penetrates far towards the south. 
It is recorded by Fewkes (1881) even from the Caribbean Sea, by A 11 man (1877) from between Cuba 
and Florida, and by Billard (1906) from the west coast of Africa. As Tubularia iudivisa is recorded 
at the same time both from the East and the West coast of North America, it must be characterized 
as a circumpolar or rather "circumboreal" (Nordgaard 1912) .species. 



Tubularia regalis Roeck. 
i860 Tubularia regalis Boeck, Videnskabsselskabets ForhandUnger for 1859. 
1899 — — -|- T variabilis Bonnevie, Norske Nordhavs-Expedition, p. 24. 

Colonies whose long, dark-brown-coloured hydrocauli are in the lower parts twisted together. 

The stem is covered with a vigorous periderm, but shows no rings nor wrinkles. No collar is formed 

4 

The Ingolf-Expedition. V, 6. 



26 



HYDROIDA 



below the polyp. The polyp wears a basal whorl of 20-35 tentacles up to 40 mm. long; the distal 
tentacles, up to 3 mm. long, are densely crowded round the orifice in a whorl consisting of several rows. 
The female gonophores are eumedusoid with 3—6 external longitudinal ribs and as many 
corresponding radial canals. The male gonophores are cryptomedusoid and oval, often with an attempt 
to be pointed in the distal part. The gonophores are born upon up to 20 blastostyles, which attain a 
length of 35 mm. The actinula larvae, when deliberated, wear filiform tentacles. 

Material : 

Between the Faroe Islands and the Shetlands, depth 505 fathoms. 

Tubularia rrgalis presents so many points of resemblance to Tubnlaria iiidivisa that the risk of 
confounding the two species is very easily incurred. As a general rule, the jfuU-grown polyps of Tn- 




200 m. _.». 600m. ._._.«._._. looom. 2000m. 

Text-fig. R. The occurence of Tuhularia regalis in the Northern Atlantic. 



biilaria regalis arc larger than tliose of Tubularia indivisa. But this is not the case in younger 
individuals of Tuhilaria regalis^ in which consequently the only certain distinguishing marks are pre- 
sented by the gonophores. The gonophores, indeed, are typical enough in the female individuals, but 
arc not very conspicuous in the male ones, esiDccially at earlier stages. The male gonophores of Tii- 
bularia regalis are oval, while those of Tubularia indivisa. are globular. It is evident from the diag- 
nosis of the species, that also Tubularia regalis presents a strong sexual dimorphism. The first who 
got aware of this fact, was vSwenander (1903), who accordingly pointed out that the female had been 
described as a different species Tubularia variabilis Bonne vie. 

Tibularia regalis is a form of true Arctic character, particularly occurring in the deeper 
parts of the cold area. In the seas far towards the north it rises to shallower parts, and it is, for instance. 



HYDROIDA 27 



recorded from Spitzbergeii at the depth of only 38 m. (Rroch 1909). Evidence of its occurrence 
in the Kara Sea is still wanting. From this locality a specimen is in hand, determined by Bergh 
(1887) as Tnbidaria rcgalis. As a matter of fact, the specimen is a Corymorpha, probably a Cory- 
niorplia glacialis M. Sars. — A remarkable exception to the habitat stated is formed by the frequent 
occurrence of the species in the Trondhjem Fjord, where it is found in abinidance on the Lophohclia- 
reefs. In spite of the luxuriant development which it attains in the Trondhjem Fjord, it must probably, 
like Coryinorplia grocnlandica (A lima n), Myriuflirhi phrygia (I'-ab r i ci us), awA Stcgopotna plicatilc 
(G. O. Sars), be accounted for as an arctic relict in this locality. 

Tubularia larynx Ellis et Solauder. 
1786 Tubularia larynx^ Ellis et Solauder, The Natural History of Many Curious and Uncommon 

Zoophytes, p. 3T. 
1864 — liuiiiilis^ Allman, Notes on Hydroida, p. 57 and 60. 

Colonies whose long polyp stems, generally unbranched and irregularly curved, are separated 
quite down to the tangled network of basal tubes. The stems are covered with a fairly vigorous, but 
colourless perisarc, which is irregularly wrinkled or more rarely quite smooth. The polyp wears a 
basal whorl of up to 25 tentacles, attaining a length of 8 mm.; the numerous distal tentacles, 2 or 3 
mm. long, are densely crowded round the orifice in a whorl consisting of several rows. 

The gonophores are euniedusoid, without radial canals, but with a rudimentary circular canal; 
they are most frequently provided with three rudimentary tentacles. The gonophores are supported by 
6—12 short blastostyles, which may be erect or hanging. The actinula larvae, when deliberated, show 
filiform tentacles. 

Material: 

Iceland: Reykjavik. 

Gustsey tiepth 4 fath. 

Keflavik - 15-16 - 

Faxebugt three miles N 37 E Keflavik — 19,5 — 

Off Havnefjord — 25 — 

Stykkisholm — 20-30 - 

Skagi - 40 '"• 

Vestman Islands — 28 fath. 

The Faroe Islands: Andefjord 10—23 

The North Sea 6o°35' N., i°5o' W — 5° — 

The synonymy of the varying species has been thoroughly accounted for by Fenchel {1905). 
He points out that, as is also maintained by Bonuevie (1899) and by Swenander (1903), Tubularia 
coronata Abildgaard must be subsumed under Tubularia larynx. On the other hand, it is not planily 
seen whether he regards Tubularia /mm His Allman to be a peculiar .species. On a closer exami- 
nation, indeed, the characters pointed out by Bonne vie (1899) as distinguishing marks, prove to 
be of no particular svstematic importance. The wrinkling of the stem is strongly varying from 

4* 



28 



HYDROIDA 



one individual to another in a larger colony, and individuals with quite smooth stems are not seldom 
observed in colonies which are otherwise typical Tuhilaria larynx. The dimensions of Tubularia Inimilis 
wholly agree with those of young colonies of Tubularia larynx, and the numbers stated as characteristics 
stand far within the range of variability known in this species. Then only remains the condition of 
the blastostyles, which should be erect in Tubularia liuiuilis, but hanging in Tubularia larynx. An 
examination, however, of living material will show that only in rare cases the blastostyles of Tubidaria 
larynx can be described as hanging (comp. Broch 1911); on the contrary they are generally borne in a 
rather erect position, particularly when not yet very large. Thus also this criterion proves to fail, 
and consequently we are forced to consider Tubularia liuinilis as a synonyme of Tubularia larynx. 

Tubularia larynx is an entire!)' boreal species, which h^s its main occurrence in the zone of the 




200 m. ___.- boom ....«._._._.looo in. . ._ . 2000 m 

Text-fig. F. The distribution of Tttbularia larynx in the Northern Atlantic. 

laminaria and the red algae. Towards the south it enters into the Mediterranean, and towards the 
north it penetrates as far as Nova Zembla, and seems still to occur at Spitzbergen. On the south- 
western coasts of Iceland it is very frequent, and it is also found on the east coast of North America. 
It is to be wondered that the species has not yet been met with at Greenland. 



Tubularia .sp. iudet. 
Stems of Tubularia of the type indivisa-regalis are in hand from the following localities: 
"Ingolf" St. 8. 63°56' N., 24^40' W., depth 136 fathoms, + 6°o C. 

- - 35- 65° 16' - 55°05' - - 362 - + 3% - 

- - 36. 61V - 56°2i' - - 1435 - + i°5 - 



HYDROIDA 



29 



"Ingolf" vSt. 40. 62°oo' N., 2i°36' W., depth 845 fathoms, + ^t, C. 

- - 86. 65°o3'6 - 23°47'6 - _ 76 - ? 

— - 87. 65°o3'2 - 23°56'2 - — no — ? 

- 106. 65°34' - 8°54' - _ 447 _ ^ 0% C. 

- - 127. 66°33' - 2o°05' - _ 44 _ ^ 5O6 - 

— - 143- 62^58' - 7°09' - — 388 - H- (r4 - 
Of a type like that of Tiibiilaria cor>iucopia Bonne vie from the locaHties: 

"Ingolf St. II. 64^34' N., 31° 1 2' W., depth 1300 fathoms, + i°6 C. 

— - 18. 6i°44' - 3o°29' - - 1 135 — + 3°o - 



Gen. Corymorpha M. Sars. 

Solitary hydroids, whose contractile hydrocaulus is surrounded by a flexible, thin, and membran- 
aceous perisarc. The hydrocaulus is attached to the substratum by numerous rhizoids. The structure 
of the polyp is radially symmetrical with two main whorls of tentacles, a proximal or basal whorl 
of long tentacles supported by a mesogloeal ring in the pol)p bod}', and a distal whorl of short ten- 
tacles round the orifice. In the full-grown polyp all the tentacles are filiform; in the actiuula 
larva at any rate the distal (oral) tentacles may be capitate. The gonophores are generally supported 
by blastostyles; the gonaiigia arise from the body of the polyp between the tentacle whorls. 

As early as 1909 I stated this limitation of the genus, grouping at the same time the species, 
on the ground of gonophoral matters, in four subgenera. However, I suggested that, as to the rela- 
tions between the two subgenera Moiiocaiilus and Lanipra^ a closer inquiry was wanting. As a matter 
of fact, one of the species stated by Allman (1876) Monocaulus groenlandica really proves to be 
identical with two of the species of Lainpra stated by Bonnevie (1899). Also the other northern spe- 
cies of Moiiocaulus has met a peculiar fate, being first ranked by Allman (1S72) within his genus as 
Monocaulus glacialis (M. Sars), and afterwards (1876), after the examination of some specimens from 
the museum of Copenhagen, described as a new species, Avialthaea islandica Allman. 

These matters, indeed, throw a glaring light on the unmaintaiuability of the subdivision into 
so-called "genera" to which Corymorpha has been the subject. At the first glance it is a matter of sur- 
prise that Stechow (1913) still tries to maintain the old genera. Indeed, in zoology more considera- 
tion must be given to the observations made on living individuals than has hitherto been done. Thus 
the two main criteria turned to account by Stechow (1912) for the purpose of distingui.shiug Cory- 
morpha ^arj// Steenstrup (1854) and Corymorpha vardocnsis Loman (1889) te-stify to the fact that 
matters of contraction are still allowed to plaj- a prominent part as to the limitation of species. By 
the observation of a living Corymorpha it will soon be ascertained that, by extension and contraction 
of the lower parts of the polyp and of the upper sections of the stem, the same polyp will show now 
a more emphatic distinction from its stem, now a smoother transition into it. The points of difference de- 
lineated by Stechow (1912, Taf. 12, Fig. 2 and 3) are, in this respect, not so great as those which 
may be observed in a single individual while alive. The other main character, that the spadix of the 



-Q HYDROIDA 



son 



ophore of Coryiiiorpha Sarsii is "fast immer" projecting from the iimbrellar cavity, while this is 
"fast nie" the case with Corymorpha vardocnsis, is in the first place very vagne, and secondly depend- 
ent partly on the varions contraction of the umbrella, parth- on the sex and the degree of maturity 
of the gonophore. On the whole there can be no doubt that the description of Corymorpha varddensis 
is based on an individual of Coryiiiorp/ia Sarsii. 

I have entered on this subject because vStechow (1912, 1913) puts together the species menti- 
oned into a genus of their own, Amalthaca. The genus was first established by O. Schmidt (1854) for the 
species Amalthaea ?«'//'i'm O. Schmidt, which is likely to be identical with Corymorpha Sarsii. Item- 
braces the species of Coryvwrplia whose gonophores develop into complete medusae, but, after all, not 
breaking away, whereas the species whose medusae are normally breaking away, are gathered in the 
genus more narrowly limited, Corymorpha. It is evident,however, that the medusa of Amalthaea excep- 
tionally breaks away and then leads a wretched life, unfit as it is for free existence on account of 
possessing a too small umbrella, the greater part of which is, into the bargain, occupied by the enormous 
spadix with mature generative cells. The medusa strongly reduced, further, shows so near a rela- 
tionship to the medusa of Corymorpha nutans M. Sars that a systematist of medusae so skilful and 
discerning as Hartlaub (1907) decides on only placing it in a subgenus of the medusoid genus 
Corymorpha. The classification afterwards maintained by Mayer (1910), who distinguishes the two 
groups of medusae as peculiar genera and even places them in quite different places in his syn- 
opsis, as Amaltliaca and Stccnstrupia., only proves that he has failed to notice the excellent drawing 
by M. Sars (1877), which shows us in fact, that the female gonophore, when fvdly developed, is often 
an entirely typical Straistrtipia, though one of the main tentacles is not quite so large as in Cory- 
morpha nutans. The figures delineated by Sars wholly agree with the facts observed in living 
individuals, and make good the correctness of Hartlaub's view of division, giving the right place 
to affinity and biology. But where is then the fundamentum divisionis adaptable for the purpose of 
classifying the Corymorpha-V^^ species of polyps into separate genera? 

From Amalthaca to Monocaulus glacialis there is, indeed, a very short step; all the difference, 
as a matter of fact, is to be found in the gonophore, also here eumedusoid, being even somewhat more 
reduced, as the tentacles, the special organs of the umbrellar margin, are entirely wanting. The con- 
formity of the polyps is obvious; the gonophores of both species are eumedusoid and normally sessile; 
the difference is accordingly too little for a separation of genera. 

Then only remains the group of Lampra^ whose gonophores are cryptomedusoid. A generic 
separation between, for instance, the species of Lampra and Corymorpha {Monocaulus) glacialis, will, 
as I have recently pointed out {1915), correspond to a generic separation between c? and '^ in Tuhu- 
laria indivisa Linne or Tubularia regalis Boeck. A particular argumentation of the inniaturalness 
of this limitation is hardly required. But then it is obvious, as a matter of course, that a generic 
separation of the species of Lampra and the other species of Corymorpha cannot be maintained. Also 
the species of Lampra must be ranked within the genus Corymorpha. 



HYDROIDA 



31 



Corymorpha nutans M. vSars. 
1835 Corynwrplm nutans^ M. Sars, Beskrivelser og lagttagelser p. 7, PI. i, Fig. 3. 

The hydiocaulus, when extended, attains a height of 100 nun. It is broad at the basis, attached 
to the snbstratum by nnmerous rhizoids, and tapering upwards till it reaches its least breadth closely 
below the polyp. The basis of the polyp is broad and surrounded by a proximal whorl consisting of 
up to 50 tentacles, which, when extended, attain a length of 30 mm. The distal tentacles are small 
and placed round the orifice in a main whorl composed of several irregular circles quite closely set 

The gonophores are developed into free medusae with four radial canals, one well-developed 
tentacle and three rudimentary ones. The gonophores are developed on 15 — 20 blastostyles, arising 




200 m. bQom. ._ .looom. . zooom* 

Text-fig. G. The habitat of Corymorpha nutans in the Northern Atlantic. 
(In the hatched regions the littcrature denotes a scattered, allthough common occurence). 

closely above the proximal whorl of tentacles. The blastostj-les bear small alternating branches, each 
provided with a large number of gonophores. 

Material : 

Iceland, 16 minutes N. W. Akranes, depth 26—30 fathoms (a couple of )-oung polyps). 

The occurrence of the species is typically boreal. It is indigenous to the middle parts of the 
littoral region. Towards the north it goes along the coast of Norway as far as Lofoten and towards 
the south it penetrates to the northern parts of France. The species is recorded by Jiiderholm (1909) 
from Matotschkin Schar (Nova Zembla) at the depth of between 2 and 5 fathoms. This find is most 
peculiar and mysterious. Corymorpha nutans occurs not rarely in the North Sea, and I think Hart- 
laub (1907) is right in supposing the specimen from the North Sea recorded by me (1905) as a Cory- 



,. HYDROIDA 



morp/ia, to be in fact a young colony of Coryniiorplia iiiitaiis. Remarkably enough, the species has 
not yet been met with at the Faroe Islands; but it has been found several times on the west side of 
Iceland. At Greenland it is not likely to occur; nor has the species as yet been recorded from this 
locality. 

Corymorpha glacialis M. Sars. 
1859 Corymorpha glacialis, M. Sars, Om Ammeslaegten Corymorpha. 
1872 Monocaulns glacialis^ AUman, A Monograph of the Gymnoblastic or Tubularian Hydroids, 

P- 396- 
1876 Amalthwa islandica, Allman, Diagnoses of new Genera and Species of Hydroida, p. 256, PI. 

IX Fig. 5-6. 

? 1887 Tiibularia rcgalis, Bergh, Goplepolyper fra Kara-Havet. 

Nee 1893 Amaltkcca islandica, Levinsen, Meduser, Ctenophorer og Hydroider fra Gronlands Vestkyst, 

p. 151. 

The hydrocaulus, when extended, attains a height of 100 mm. It is wide at the base, where 

it is attached to the substratum by numerous rhizoids, and is gradually tapering upwards till closely 

below the pol>-p where its width reaches its minimum. The polyp has a broad base, surrounded by a 

whorl of up to 50 tentacles, which, when extended, attain a length of 30 mm. The distal tentacles are 

small and numerous, placed round the orifice in a main whorl formed by several irregular and closely 

set circles. 

The gonophores are eumedusoid, with four radial canals, but without rudiments of tentacles. 

They are sessile. The gonophores are scattered all over the surface of 30—35 unbranched blastostyles, 

the oldest and most developed ones at the apex of the blastostyle. 

Material : 

Iceland, 0fjord (without particular data). Original specimen of Amalthaca islandica. 
?The Kara Sea ("Dijmphna". Particular data are wanting). L,abelled Tuhilaria rcgalis. 

The original specimen in hand of ^linalthaca islaiidica Allman (1876) proves as clearly as de- 
sirable that this species is wholly identical with Corymorpha glacialis. Allman, certainly, states that 
the gonophores of the species are provided with four short tentacles, which are also, in his rather 
skeletonlikc drawings, delineated as rather considerable formations. But in the original specimen can 
only in some straggling gonophores be pointed out some accidental wrinkles, wliich, when acting in 
good will, we may consider as the origin of the rudimentary tentacles stated. Other divergencies from 
the typical Corymorpha glacialis are, on the whole, not traceable. 

A specimen from the Kara Sea has been identified by Bergh (1887) as Tiibularia rrgalis Boeck. 
The sjjecimcn is an unquestionable Corymorpha and no Tiibularia\ indeed, everything suggests that 
it is a Corymorpha glacialis, l)ut the state of preservation impedes a safe identification. 

According to the particulars in hand Corymorpha glacialis is indigenous mainly to Arctic wa- 
ters. It has been recorded from the Varanger fjord (M. Sars 1859), from Nova Zembla (Maren- 
zeller 1877), ^"'^ from .Spitzbergen (Broch 1909). But the species also penetrates into warmer water 



HYDROIDA 



33 



layers, as is seen (Text-fig. H) from the finds to the north east of the Faroe Islands and on the south 
east coast of Iceland (Broch 1903). As new localities must be added Northern Iceland (0fjord). On 
the other hand, the specimens from Davis Strait, recorded by Levinsen (1893) as AniaUhaca islandica, 
prove to belong to Coryinorpha groenlandica (Allnian). 



Corymorpha groenlandica (Allnian) Broch. 
1876. Monocaulus groenlandica^ Allnian, Diagnoses of new Genera and Species of Hydroida, p. 257, 

PI. IX, Fig. 7—8. 
1893. Amalthcra islandica -^ Monocanliis groenlandica, Levinsen, Mednser, Ctenophorer og Hydroider 

fra Groulands Vestkyst, p. 151. 




loom. boom. .. looom. Jooom. 

Test-fig. H. Finds of Corymorpha glacialis iu tlie Northern Atlantic. 

1899 Lainpra atlantica + Laiupra purpurea, Bonnevie, Nor.ske Nordhavs-Expedition, p. 20, Tab. II 

Fig. 4, Tab. Ill Fig. t. 
1903 — socia, Swenander, Uber die athecaten Hydroiden des Drontheimsfjordes, p. 6, Taf. 

Fig- 1—3- 
1909 — arctica, Jaderholni, Hydroiden, p. 41, Taf. I Fig. 9—10. 
1909 Corymorpha spitzbergensis, Broch, Die Hydroiden der arktischen Meere, p. 140. 
igi^ _ groenlandica, Broch, Hjdroiduntersuchungen IV, p. n. 

The hydrocaulus, when extended, attains a height of 100 mm; it is widest at the base, where 
it is attached to the substratum by numerous rhizoids, and is gradually tapering upwards till close 
below the polyp where the width reaches its minimum. The polyp has a wide base, surrounded by 

5 

The Ingolf-E.\pedition. V. 6. 



34 



HYDROIDA 



a basal whorl of up to 37 tentacles, which, when extended, attain a length of 40 mm. The distal ten- 
tacles, when extended, attain a length of 9 mm; they are placed in large numbers round the mouth 
in a main whorl formed by two or more irregular and closely set circles. 

The gonophores are cryptomedusoid and globular (?) or sub-oval (c?), often somewhat tapering 
distally, but without any rudiments of tentacles. The gonophores are supported by unbranched and 
strongly contractile blastostyles, which, when extended, attain a lengtli of 40 mm. The gonophores 
first ripen at the apex of the blastostyle. As many as 32 blastostyles may occur, but, in general, the 
number is much smaller; the blastostyles arise close above the basal whorl of tentacles. 

Material: 

"Ingolf vSt. 102. 66°23' N., io°26' W., depth 750 fatho'ms, -^ o°9 C. 

- 107- 65°33' - io°28' - - 492 - -^ o°3 - 

- 139- 63^36' - 7°3o' - - 702 - -- o°6 - 

Greenland: Godthaab (no particulars) [Allman's original specimen oi Moiiocaidus groenlandica\. 

Davis Strait, depth 100 fathoms [labelled Aiiialtliaca islandica]. 
Iceland: 66°02' N., ii°05' W. 

5 miles east of Seydisfjord; depth 435 fathoms. 

The fairly well preserved specimens of the material recently collected show the following cha- 
racters (all the measurements are given in mm). 



Nr 


Finds 


Height of 
Hydro- 
caulus 


Blastostyles 


Proximal Tentacles 


Distal Tentacles 




Obsen-ations 




Number 


Length 


Number 


Length 


Arrangement 


Length 




I 


"IiiKolf ' vSt. 139 


90 


14 


5 


? 


? 


in several close circles 


2 


Hydrocaulus strongly 
extended 


2 


"Ingolf St. 139 


60 


15 


1-3 


? 


? 


in several close circles 


2 


Blastostyles very strong- 
ly contracted 


3 


"Ingolf" St. 107 


57 


13 


3-5 


26 


25 


in a double circle formed by 
alternating displacement 


1-5 




4 


"Ingolf' St. 102 


45 


10 


5 


23 


up to 24 


in several close circles 


1-5 




5 


"Ingolf" St. 102 


41 


8 


5 


25 


24 


in a double row formed by 
alternating displacement 


2 




6 


Davis Strait 


40 


20 


7 


24 


25 


in several close circles 


5 




7 


"Ingolf St. 107 


? 


10 


6-13 


21 


30 


in three irregular rows formed 
by alternating displacement 


1-5 


Hydrocaulus more than 
50 mm high 


8 


"Ingolf St. 102 


? 


9 


4 


28 


up to 23 


in several close circles 


2 




9 


"Ingolf St. 107 


? 


:6 


3-4 


24 


22 


in a double row formed by 
alternating displacement 


2-5 




10 


66°2'N.ii°o5'W. 


28 


5-18 


22 


25-30 


? 


? 


Blastostyles placed alt- 
ernatingly ; attempt 
at forming two rows 


1 1 


"Ingolf" St. 107 


? 


14 


4 


IS 


iS 


in three irrfjj;ukir rows formed 
by alternating displacement 


2 





HYDROIDA 



35 



The species, which is widely distributed in the deejDer parts of the cold area, has been found by 
several expeditions, and has formed the base of the genus Lampra stated by Bonne vie (1898, 1899). 
I have already in works earlier published pointed out that, for several reasons, this genus cannot be 
maintained. In the first place, the name of Lampra had already been applied to a subgenus of the 
beetle family Bitprcstidac^ and should, therefore, disappear amou.»- the hydroids, according to the rules 
of nomenclature internationally adopted. Secondly the character.s distinguishing Lauifra from Cory- 
morpha are not sufficient to justify a separation of genera. 

A closer examination of the numerous northern species of Lampra described will show their mi- 
maintainability. A survey of the figures forming distinguishing characters is obtained by grouping the 
criteria stated as follows: 



Nomenclature 


Height of 
Hydro- 
caulus 


Blastostyles 


Tentacles 
Proximal Distal 


Gonophores 




Number 


Length 


Number 


Length 11 Arrangement 


Length 




MonO'-nulus groenlandica All man 1S76 . 


I inch 


7-8 


? 


ca. 20 


"Modera- 
telj'long" 


"numerous" 


short 


no tentacles 


Lampra arctka Jaderholm 1909 


45 mm 


22 


5—8 mm 


25 


25 mm 


5-5 close circles 


> 


globular.broadlyoval 
with rounded apex 


Corymorpha spitzbergensis Broch 1909. . 


60 mm 


12 


5 mm 


25 


20 mm 


4-S close circles 


2 mm 


oviform or globular 
without tentacles 


Lampra atlantka Bonne vie 1899 .... 


80 mm 


10 


4—6 mm 


10 


10-20 mm 


several close- 
set circle 


? 


without tentacles 


Lampra purpurea Bonnevie 1899 


100 mm 


10 


30-40 mm 


30 


30-40 mm 


two circles 


? 


without tentacles 


Lampra socia S w e u a n d e r 1903 


45 mm 


18-32 


till 25 mm 


29-37 


35 mm 


numerous 
close-set circles 


up to 
9 mm 


9 more rounded, 

<S sub-oval, 
without tentacles 



The original discription given by Allman (1876) is founded on a series of young individuals 
from Godthaab, in which it may be observed how the number of pro.ximal tentacles increases by new 
tentacles being established and growing out among the old ones. How far the number of tentacles 
may increase in this way, cannot be settled. But no definite rule of the increase being trace- 
able, we here face one of the reasons of the great varying of the numbers of tentacles. In these young 
individuals it is also interesting to observe that the distal tentacles are established quite irregularly 
Tab. II Fig. 14), and that the blastostyles arise as simple fiugerformed bulges of the polyp wall. The 
gonophores only appear at a rather late stage of development. 

The skeletonlike figures and rather deficient diagnosis of the species given by Allman long 
impeded its recognition, and, therefore, only a couple of specimens occurring in the museum of Copen- 
hagen have later on been correctly referred to his species Monocaulus groenlandica. Bonnevie (1899) 
accordingly describes two new, closely related species, LMmpra atlantka and L.ampra purpurea. The 
former species is distinguished from the latter mainly by its small number of tentacles, having only 
ten proximal ones. However, even though this difference must be regarded as very large, as far as ni 
the single specimen of Lampra purpurea as many as thirty proximal tentacles have been observed, 
we cannot acknowledge it as a sufficient specifical distinguishing character after the examination of a 
larger material of the species. The rather numerous specimens found in the Trondhjem fjord present 



36 



HYDROIDA 



SO great a range of variability that the number stated in Lainpni af/aiifica must only be considered 
as an extreme variation. The variation of the individuals found in the Trondhjem fjord is even larger 
than stated by Swenander (1903); individuals have been found with only 15 tentacles in the proximal 
whorl. The difference in the shape of the gonophores, being either subglobular or oval with attempts 
at tapering, is of Httle importance. Swenander points out that the female gonophores are more 
globose, the male more oval. In a specimen picked up north east of the Seydisfjord (Iceland) the gono- 
phores are partly globular, partly oval, with the same attempt at tapering towards the distal end as 
is shown in the figure of Bonnevie (1899, Tab. Ill, Fig. i a). However, one criterion is still left, 
the distal tentacles of Lampra purpurea being arranged in two separate circles, while in other spe- 
cies they are placed in several irregular and close-set circles. From the comments of Bonnevie it 
appears that the description has mainly been based on the drawings of G. O. Sars, which were exe- 
cuted on board ship. In these drawings the double whorl is not peculiarly clearly rendered ; nor can, 
from the remnants of the original specimen kept, the character be ascertained any longer. From the 
table set up of the specimens from the Danish collections, however, it appears that, from individuals 
with a distal whorl consisting of two rows to individuals with a distal tentacle whorl of several rows, 
every transition may be pointed out. Thus neither this table nor the criteria stated in the other table 
may be turned to account for the jjurpose of attaching any peculiar systematical importance to this 
character. Lampra atlantica and Lajiipra purpurea, therefore, cannot be recognized as two sepai^ate 
species, and are moreover identical with Corymorpha groenlandica. 

For a thorough examination of the species we are indebted to .Swenander (1903), who considered 
the Lampra of the Trondhjem fjord as a peculiar species, Lampra socia. From what I have stated 
above, the shape of the gonophores, applied by Swenander as a main character distinguishing the 
species from Lampra purpurea Bonnevie, cannot be maintained as a criterion. The number of the 
blastostyles then remains; Bonnevie, for both the species mentioned, states 10 blastostyles ; Swen- 
ander, for La7npra socia, 18 — 32. Still Swenander has not found the minimum for the individuals 
of the Trondhjem fjord; as a matter of fact, specimens with only 15 blastostyles are now in hand. 
In the Danish material collected from the northern Atlantic the number is throughout lower, varying 
from 10 to 28, thus bridging the difference between Lampra socia and the species stated by Bonne- 
vie. Also the other distinguishing characters, the emphatic demarkation of the hydrocaulus from the 
polyp, or its gradual transition into the latter, and the colour of the animals, are varying from one 
individual to the other, forming no strongly defined limits. The demarkation of the stem from the 
])olyp more or less emphatic, is, in living individuals, varying according to the state of contraction, as 
in other species of Corymorpha. Therefore, also Lampra socia must be considered as a synonym of 
Coryvwrpha groenlandica. 

Jaderholm (1909) and Broch (1909) describe two new species, respectively Lampra arctica 
and Corymorpha spitzbcrgensis. The table at once shows that they come within the range of variation 
of Corymorpha groenlandica. As to Lampra arctica the short and thick blastostyles, maintained by 
Jaderholm (1909) as a good criterion, are in fact to be looked upon as a mere phenomenon of con- 
traction which may be partly observed even in preserved material, where in the same individual some 
blastostyles may be short and thick, while others are thin and strongly extended. Illustrative in this 



HYDROIDA 



37 



respect is the individual nr. lo of the first table, the length of the blastostyles varying from 5 to 18 
mm., and the thickness being inversely proportional to the length. The rest of the distinguishing 
characters fall under what has been earlier stated. 

Corynwrpha gronilaiidica is a typical form characteristic of the great deep of the cold area. It 
proves to be wideU' distributed, from Spitzbergen to the Faroe I.slands, and from Norway to Green- 
land. It has also been recorded from Davis Strait. In the .seas far to the nortli it ri.ses to more shallow 
waters. Thus it has been recorded near vSpitzbergen at the depth of only 45 metres (Broch 1909). 
A remarkable geographical exception is formed by the occurrence of the species in the deeper Atlantic 




300 m. t/QQn:. ■_._ 1000m. i looom. 

Text-fig. I. Localities of Corymorpha groenlavdka in the Northern Atlantic. 

Strata of the Troudhjem fjord. At present the occurrence of the species in this locality cannot be 
accounted for. But a great deal may be said in favour of the notion that we have here in hand a 
relict form, which has been able to accommodate itself to the altered circumstances in the same way 
as Ttibularia regalis Boeck and Stcgopoma plicatile (M. Sars) which are rather frequently occurring 
on or at the Lophohelia reefs of the §ord. 



Corymorpha sp. indet. 
Indeterminable remnants of species of Coryinorpha occur from the following localities: 
"Ingolf ' St. 28, 65°i4' N., 55°42' W., depth 420 fath., + 3°5 C, attached to the tube of a Pedinaria. 
- -124, 67°4o' - i5°4o' - - 495 - -=-o°6- 



38 



HYDROIDA 



Section Filif era K ii h n. 
Family Clavidae. 

Hydroids forming colonies, with polyps fnsiforna or capitate, the distal part of which is coni- 
cally tapering. The stinging cells are small and rodformed. The tentacles are filiform, irregularly dis- 
tributed over the body of the polyp, now and then showing a heterogeneous development or even 
reduced to a single large tentacle. The endoderm forms a homogeneous gastral cell-layer through 
the whole of the polyp. The colonies have no calcareous skeleton. 

The family Clavidae., as it is here defined, includes the genus much in dispute Monobrachiiiiii., 
which has been distinguished by most investigators as the representative of a family of its own, Mo- 
nobrachiidac. This family is maintained even by Kiihn (1913), who has obviously failed to notice 
the significant pointing out by Vanhoffen (1909) of the heterogeneous development of the tentacles 
of Campaniclnva cliouis Vanhoffen, forming an obvious link between Miuiobracliinm and the other Cla- 
vidae. Vanhoffen, therefore, does away with the family Moiiobrachiidar and refers Moiwbracliiuin 
to Clavidae. In this he is rightly followed by Stechow (1913). 



Gen. Clava (inielin. 

The reptaut colonies have polyps capitate or subfusiforni with filiform tentacles irregularly 
distributed over the polyp. The proboscis is conically pointed. The hydrocauli are not surrounded 
by any distinct stiff perisarc. The gonophores are clustered on the polyp below the portion bearing 
tentacles, or seated on the reptaut stolons either solitary or in clusters. 

According to this diagnosis also the genus R/iizogeloii must be included under Clava. The two 
genera have hitherto generally been distinguished on the ground that in Rhizogeton the gonophores 
are seated on the stolons, while in Clava they are borne by the polyp itself. This criterion, however, 
is too insignificant to justify a division of genera, and it is also suggested by Stechow (1913) that 
very likely the two genera have to be united. In his key of genera, indeed, Stechow puts down 
Rhizogelon in a parenthesis under Clava. 

Clava multicornis (Forskal) Gmelin. 

1775 Hydra multicornis., Forskal, Descriptiones animalium, p. 131. 

1776 — squa?nata, Miiller, Zoologia Danicae Prodromus, p. 230. 

1788 Clava parasitica., Gmelin, in Linne: Systema natura Ed. 13, vol. I, ■^. 3131. 

On the reptant stolons the capitate or almost fusiform polyps are placed in close or opener 
clusters. The stem of the polyp is without perisarc. The filiform tentacles are irregularly distributed 
over the distal parts of the polyp. 

The gonophores are cryptomedusoid, and placed in larger or smaller groups like clusters of 
grapes closely below the portion of the polyi^ bearing the tentacles. 



HYDROIDA 



39 



The species may be divided into two forms: 

Forma genuina, growing, in colonies more openly constructed, on stones and shells {My/ilus)\ 
It is delicately built and bluish or rose-coloured. 

Forma sqiiatiiata forming clusters of polyps more brick-coloured or yellowish-red on the leaves 
of Fucoideac\ its polyps are large and robustly built. 



Material: 

Iceland : Reykjavik 

Vestmanney 
The Faroe Islands: Sundelaget 

north of Kvalvik 



depth 3 — 4 fathoms, 
on the shore (on Fucoidcae) 

on the shore (on Fucoideae) 



(There also occur specimens marked "Faero" without particular data). 

Clava ?iinlficon/is and Clava sqiiainata are recorded by most investigators of hydroids as two 
separate species; the distinguishing characters, however, are rather vague, being made out by the 
closer or opener occurrence of the polyps in the colony or by the colour of the colonies. A copious 
material from various localities, in fact, presents all transitions possible, and it is virtually impossible 
to draw any certain limit between the siDecies. A closer inquiry soon makes clear to us that the 
points of difference must be of biological nature, and the two species, therefore, have to be regarded 
only as biologically determined "form.s" of a single species, which I, accordingly, denominate forma 
genuina and forma sqiiiiiata. The occurrence of typical colonies of the forma gemiina^ which are, in 




Text-fig. K. The distribution of Clava imdticornis iu the Northern Atlantic. 
(In the hatched part of the Norwegian coastal region the occurrence is rather scarce). 



AQ HYDROIDA 



fact, rather rare and scattered, is bound to substrata of stones, which may be, at a pinch, replaced by 
the shell of a Mytilus^ while the colonies luxuriantly developed of the forma squarnata are resident ou 
the leaves of the Fucoidcae, where certainly the supply of food is much more copious. 

The description of Forskal (1775) being older than that of O. F. Miiller (1876), we have 
according to the rules of nomenclature in force, to drop the specific name employed by the latter, 
Clava sqtiamata and to maintain the denomination bestowed on the species by Forskal, Clava inulti- 
cornis. Its limitation from the American species Clava Icptostyla L. Agassiz, has not as yet been 
ascertained, and it seems on the whole questionable if the two species are really to be distinguished. 

Clava multicornis is a boreal species, which seems, nevertheless, to be able to penetrate far 
into the i\Iediterranean (Babic 1904). It is a littoral form, and forma squaiiiata has beeu found only 
in the tidal zone; ioxwvA gemmia^on the other hand, at rare intervals, has been met with a little ben- 
eath the tidal zone in places with rather small salinity. F~abricius (1780) records the occurrence 
of the species at Greenland without particular statement of locality; however, it has not afterwards 
been observed in this place. On the other hand, the species seems to occur not unfrequently on the 
south west coast of Iceland. It is frequently met with at the Faroe Islands, and is found everywhere 
round the British Isles and on all coasts round the North Sea. Its occurrence at the northern parts 
of the coast of Norway is not sufficiently accounted for, but does not seem to be particularly frequent. 



Gen. Merona Norma nn. 

From the reptant stolons arise unbranched, chitinous polyp stems. In the upjDer part of the 
stem the perisarc is so wide that the polyp can be retracted into it, though developement of a hydro- 
theca is not indicated. The filiform tentacles are irregularly spread over the polyp. The gonophores 
are borne upon reduced polyps (blastostyles) arising from the reptant stolons. 

With great hesitation I set up Merona as a genus of its own. It is distinguished from Cory- 
dendrium van Beneden (1844) only in mere trifles of no great importance. Thus its polyp stems 
are unbranched, while the hydrocaulus of Corydendrium is richly branched. Another distinguishing 
character may perhaps be sought in the quality presented by Merona in its wide perisarc, into which 
the polyps are retractile. But none of these criteria can be said to be of properly generic value. When, 
nevertheless, Merona is provisionall)- maintained, it is due to the fact that only an exceedingly scarce 
material of a single .species is in hand, and that the state of preservation of this material allows of 
no closer inquiry into the polyps. 

Merona cornucopiae Norman. 

1864 Tubiclava cornucopiae, Norman, On nndescribed British Hydrozoa, Actinozoa and Polyzoa, p. 357. 

1865 Merona — Norman, On Merona, an nndescribed genus of British Hydrozoa, p. 262. 

The hydrocauli are unbranched and attain a height of about 5 mm.; the stems are narrowest 
at the base and increase gradually in diameter till they attain their greatest width closely below the 



HYDROIDA 



41 



extended polyp; they are without rings; at most there is some faint and irregular wrinkling here 
and there. The polyp is fusiform with the tentacles irregularly distributed all over the surface; the 
polyp may be retracted into the broader distal portion of the hydrocaulus. 

The structure of the gonophores seems to be strongly reduced. They are developed at the 
upper part of blastostyles without tentacles, at most i mm. high. 

Material: 

The Faroe Islands: 1^ miles West to South of Munken, depth 150 fath. (on Oirdium .sp.). 
— — 9 — East South East of Bi.spen, — 70 — ( - — - ). 




200 m. 6oof7i. ._ .._.iooom. 2000m. 

Text-fig. L. Localities o{\^A•l■o/la corimcopiac • and ilonobrachiian fiarasitiiiii ▲ in the Northern Atlantic. 

Mcrona cormicopiac was first described as a Tiibiclava by Norman (1864). But as the latter 
genus is characterized by the gonophores being borne on the polyps, he thought he had better set 
up a new genus Mcrona (1865) for the species in hand, bearing its gonophores on polyps strongly 
reduced or on blastostyles. This criterion, however, is of subordinate importance and would by no 
means justify the separation of two genera. However, from the drawings occurring in literature, a 
much essential point of difference urges itself. The perisarc of the species of Tubiclava is not so wide 
that the polyp can be retracted into it, while this is the case with Merona. The division, therefore, 
seems well founded. But at any rate a renewed examination of the two genera is needed. 

Mcrona cornucopiac seems only to occur attached to shells of living mollusks, and has been 

found on species of the genera Cardium, Astartc, and Dcntalium. The species does not seem to be 

very frequent; it has previously been recorded from the sea to the north of the Shetlands at the 

depth of 80-100 fathoms, and from the coast of Northumberland. To these locaHties are now to be 

6 

The Ingolf-Expcdition. V. 6. 



• 2 HYDROIDA 



added the>eas to the south of the Faroe Islands at the depth of 70—150 fathoms. All the finds are 
thus situated in the boreal area, on the border of the warmer Atlantic regions (Text-fig. L). 



Gen. Monobrachium Mereschkowsky. 

Reptant colonies, whose cyliudric polyps are provided with a solitary large tentacle. Besides 
the nourishing individuals bearing tentacles, also machozooids with no mouth and no tentacles occur. 
The polyps have no distinct stem and are not covered with perisarc. The gonophores are eumedusoid 
and attached to the stolons. 

The very peculiar Arctic genus of hydroids first described by Mereschkowsky (1877) has been 
more closely investigated by Wagner (1890) and Bonnevie (1899). In the only species known of this 
genus the eumedusoid gonophores have a rudimentary spadix, and the germ cells are accordingly 
developed along the radials canals. On this ground Bonnevie maintains that the species is closely 
related to the Lcpto)iicditsat\ and tliat the genus has to be placed proximately between athecate and 
thecaphore hydroid.s. Kiihn (1913), on the other hand, holds that the organisation of the gonophore 
cannot be considered as any certain proof justifying such a supposition, and points out that the trans- 
ition of the gonophore from independent free existence into sessile mode of life can effect a secondary 
displacement of the gonads in many different ways without any necessity that this should be indica- 
tive of nearer or remoter relationship. Apart from this, however, there is an additional reason against 
the supposition of Bonnevie. As is pointed out by Vanhoffen (1909), we have in hand a medusa- 
form obviously nearly related, Catablniia, which, when somewhat damaged, is very easily mistaken 
for a Lcptomednsa, but which is, in fact, a genuine Tiaridc. Vanhoffen even presumes that Cata- 
bloiia really is the medusoid generation of Mo)iobracliitiiii. But in that case it remains to show that 
the gonophores of Monobrachiiiiii arc not sessile as they have hitherto generally been supposed to be. 

The explanations of Vanhoffen (1909) and Kiihn (1913) make good that Moiiobrachi/iiii takes 
no intermediate place between athecate and thecaphore hydroids. But the place of the genus among 
the athecate hydroids would still be equally uncertain if the peculiar .species Cavipaniclava clioiiis 
Vanhoffen (1909) had not shown u.s, by its heterogeneous development of the tentacles, the unquesti- 
onable link between Monobrachiuvi and the normal-looking forms of Clava. Therefore there is no 
reason any longer to regard the genus as the representative of a jDeculiar family; as pointed out by 
Vanhoffen, it ought to be classed with the Clavidac. 

Monobrachium parasitum Mereschkowsky. 
1877 Moiiobracliiuvi parasitiiDi, Mereschkowsky, On a new Genus of Hydroids, p. 225, pi. 5 fig. 1—6 

pi. 6 fig. 7—14. 
1899 — parasitiaini Bonnevie, Norske Nordhavs Expedition, p. 51. 

Reptant colonics, whose polyps are dimorphically developed; beside cyliudric polyps with ori- 
fice and a vigorous tentacle, also machozooids without mouth or tentacles occur. The nourishing 



HYDROIDA . , 

43 



Ijolyps are provided with a ring of stinging cells above the base of the tentacle. The stolons form a 
network of anastomosing tubes. 

The gonophores are eumedusoid with a rudimentary spadix and with the generative cells 
placed along the four radial canals. The colonies are bisexual. 

Material: 

Greenland: Egedesminde (on Trllina calcarea). 

The Kara Sea ("Dijmphna"). 

MoiwhracIiiiDii parasifiiiii is indigenous to the middle parts of the litoral region far to the north. 
It is recorded from Spitzbergen, the Kara Sea, the White Sea, and the west coast of Greenland 
(Text-fig. L). 

Family Bougainvilliidae. 

Hydroids forming colonies with polyps fusiform or capitate, whose oral portion is conically 
pointed. The stinging cells are small and rodshaped. The tentacles, which are filiform, are placed in 
a main whorl round the pol)p; the stinging cells are equally distributed all over the surface of the 
polyps or in less distinct transverse belts round them. The 23olyps are quite naked or surrounded by 
a jellied, lithe, and pliable pseudohydrotheca below the tentacle whorl. The endoderm is differentiated 
into an oral portion, consisting of indifferent small-nucleated cells between which occur a large number 
of mucous gland cells, and the proper gastral portion; the limit is formed by the tentacle whorl. The 
colonies have no calcareous skeleton. 

The diagnosis states for the family the same range as was practically already given by Bon- 
uevie(i899), whom the later authors have generally followed. Kiihn (1913) divides the family into 
three subfamilies, two of which, IIy(h-actiiiii)iac and Atractyliiine^ are represented in our northern seas. 
The main distinguishing mark stated by Kiihn is that Ilydrdcfii/iinac are stated to have a vigorou.s, 
crustformed skeleton, while ^itractyliinu^ on the other hand, have h)'drocauli covered with periderm. 
However, this character does not seem to be of the importance Kiihn attached to it. In young 
colonies the stolons have not coalesced into a crust, and the development of the skeleton is not parti- 
cularly vigorous. There is even every probability that several species of Stylactis do not at all assume 
such crustformed skeleton-formations, even when advanced in life. On the other hand, we also know 
species of Hydradiniinae, in which the hydrocaulus covered with periderm has been reduced to a mere 
minimum. The character, therefore, must be characterized as a merely gradual one, and can hardly be 
turned to account as fundamentum divisionis for higher groups. 

A very different interest is attached to the peculiar occurrence of pseudohydrothecae met with 
in the Bongainvilliidac. I set aside the socalled pseudohydrothecae of Clathrozoon (the subfamily Ily- 
droccratiiiiiiac, stated by Kiihn 1913); in fact, this group is not yet so well known that we are able 
to judge of it entirely, and its "pseudohydrothecae" do not seem to form such a parallel with the for- 
mations of the thecaphores as those found in certain other Bougainvilliidac , namely in Pcrigo- 
nimus. In this species the ectoderm of the polyp has secerned a jellied pseudoh>drotheca, which has 
coalesced with the polyp along its distal margin, and to which the basal portion of the supporting 



.. HYDROIDA 

44 



lamella of the polyp is attached by small chitinous bodies similar to those found in several thecaphores. 
This psendohydrotheca is but little visible, or, with intact polyps, when they are extended, almost 
untraceable, while in contracted polyps it lies round the basal portion of the polyp like a cup richly 
folded. It might be obvious to regard it as the precursor of the real hydrotheca. Perhaps it might 
be regarded as a character sufficiently important for the purpose of distinguishing a subfamily: How- 
ever, the matter has, as yet, been too little examined as to allow the forming of a reasonable opinion; 
we have, provisionally, to regard it as a generic character. 



Gen. Hydractinia van Bencdcn. 

The stolons of the reptant colonies, when young, will generally form an open meshwork which 
afterwards most frequently changes into a continuous chitinous crust. The crust is commonly carrying 
spines of various appearance, or may grow out into branched formations of colonies. The polyps are 
cylindrical or capitate with conically pointed oral portion. The tentacles are placed in a whorl below 
the mouth. There is no erect hydrocaulus covered with perisarc. The polyps are heterogeneonsly devel- 
oped into larger nourishing individuals bearing tentacles and into spiralzooids bearing no tentacles; the 
latter occur at the extremities of the colonies. — The gonophores are supported by polyps more or 
less transformed (blastostyles) or arise directly from the stolons. 

According to this diagnosis, also Podocoryiic, Oorhiza and Stylactis^ earlier set up as genera 
are included under Hydractinia. The only reason of distinguishing between Hydractinia and Podo- 
corync has been sought in the power of the last-mentioned genus of producing free-swimming medusae. 
However, Bonnevie (1899) has described a couple of species, Hydractinia Allmani and Hydractinia 
ornata, having medusoid gonophores less strongly reduced with radial canals, and from Africa has 
been recorded a species, Hydractinia Michaelseni Broch (1914), whose male gonophores are perfect 
medusae, which, however, do not seem to break away normally. Also Kiihn (1913) seems to incline 
to the opinion that the separation of the two genera is questionable. The intermediate forms of gono- 
phores mentioned, in fact, forbid the drawing of a certain limit between the genera, and, therefore, the 
proper thing to be done, is, indeed, to draw in Podocoryne under Hydractinia. 

The genus Oorhiza is based on the fact that the gonophores are seated, not, as in Hydrac- 
tinia, on blastostyles, but, on the contrary, on a short stem rising directly from the stolons. A review 
of our northern species of Hydractinia., however, shows that, in fact, this criterion is of no vital im- 
portance. In Hydractinia Inimilis Bonnevie and Hydractinia Sarsii Steenstrup the gonophores 
are l)orne on polyps fully developed of the same size as the sterile nourishing individuals; in Hy- 
dractinia carnea M. Sars the polyps bearing gonophores are, certainly, fully developed individuals, 
provided with tentacles; but Ihcy have a smaller number of tentacles, and are smaller than the sterile 
nourishing polyps. In Hydractinia Allmani Bonnevie, Hydractinia ornata Bonnevie, and Hydrac- 
tinia echinata (Fleming) the reduction is carried still further, the tentacles being reduced or wholly 
disappearing, so that the bearers of the gonophores are here typical blastostyles. In Hydractinia carica 
Bergh, finally, the pol)p has been reduced to a stem, round the apex of which the gonophores are 



HYDROIDA .c 

45 



placed in a whorl. In fact, between this condition of things and a solitary gonopiiore seated termin- 
ally on a polyp wholly reduced to a stalk, there is no great gap, and at any rate the criterion is not 
essential enongh to be tnrned to account as fundamentuni divisionis. Also Oorhiza has, accordingly, 
to be included as a synonym under Hydractinia. 

Stylactis is yet left to be mentioned, being distinguished by the stolons forming an open mesh- 
work and no continuous chitinous crust. In his excellent elucidation of Hydractinia and Podocorync^ 
Hi neks (i86S) calls attention to the fact that, in the species then known, the stolons at first form 
an open mesh-work and do not till later on coalesce into a continuous crust. Young colonies of Ilydractinia 
carnea, which are in our Norwegian seas very connnonly observed on living specimens of Nassa reticu- 
lata^ in most cases show this open mesh-work of stolons and, therefore, easily run the risk of being 
undiscerningly characterized as Stylactis. In the African species, Hydractinia Michaelseni Broch 
and Hydractinia fallax Broch, large colonies show a mixture of characters of Stylactis and of Hy- 
dractinia, and, accordingly, there is no reason to maintain the two groups as distinct genera. They 
communicate with each other by intermediate forms. It is probable that several species of Stylactis 
have been based on young colonies of typical species of Hydractinia. This probability, indeed, cannot 
be contested even by the occurrence of gonophores, because, in young colonies of Hydractinia carnca, 
where the stolons have not yet coalesced into a crust, gonophores are frequently observed. A species 
as Stylactis arctica Jiiderholm (1902) has obviously to be judged summarily as such a young Hy- 
dractinia. Also Stylactis, therefore, has to be included among the synon)-ms of Hydractinia. 

Hydractinia Sarsii (vSteenstrup) Bonnevie. 

1846 Podocoryna carnca, M. Sars, Fauna littoralis Norvegite, Heft i, p. 7. 

1850 Podocorynr Sarsii, Steenstrnp, in: Liitken, Nogle Bemasrkninger om Medusernes systematiske 

Inddeling, p. 33. 

1872 Stylactis — Allnian, Monograph of the Gymnoblastic or Tubularian Hydroids, p. 303. 

1892 Podocoryne carnca, Leviusen, Meduser, Ctenophorer og Hydroider fra Gronlands Vestkyst, p. 11. 
1899 — — Pai^s, Stemundsson, Bidrag til Kundskaben om de islaudske Hydroider, p. 50. 

1899 Hydractinia sarsii, Bonnevie, Nonske Nordhavs Expedition, p. 45. 

The reptant stolons are covered by a continuous chitinous coenosarc, whose surface is studded 
with small spines, among which are found, often b}- groups, large, vigorous thorns, up to 0.5 mm. high, 
of irregular conical shape with closed apex abruptly cut off. The poljps attain a length of 2.5 mm. 
and have 10 or 20 tentacles in a dense, proximately double, whorl, below the oral portion. Spiral- 
zooids have not yet been pointed out. 

The gonophores are cryptomedusoid and placed, to the number of three or six, round fully 
developed polyps of the same size as the sterile nourishing individuals. 

Material : 

Greenland, the harbour of Godthaab . . . depth 12 fath. (on Hyas arancus). 
Iceland, Seydisfjord (o" Carcinus maenas). 



46 



HYDROIDA 



The well developed colony in hand has been wrongly determined as Podocorync cornea. It is 
hardly intelligible that Bedot, in his "Materianx pour servir a I'histoire des Hydroides", should have 
followed All man (1872) and referred this species to Sfylaciis ; it is one of the few species of Hy- 
dractinia which, even at the extremities of small colonies, show no indication of the open network of 
stolons for which Stylactis should be distinguished. 

The species seems to be a boreal one, but it has hitherto been recorded only from very few 
localities, as it has probably been mistaken for Hydractiiiia carnca also by investigators subsequent to 
M. Sars (1846). It has previously been recorded only from the coast of Norway near Bergen. In the 
Danish collections is found a well developed, though sterile, colony from Iceland (Seydisfjord), 
seated on the claw of a strand-crab. It seems to be the samf species which is recorded, by the name 




200 m, 600m. .. 1000 m. 

Text-fig. M. Finds of Hydractinia Sarxi • end Hydractinia caricii A 



2 000 m. 

the Northern Atlantic. 



of Podocorync carnca., from the north of Iceland, on the operculum of a Balamts Ihninncri (vStemund.s- 
son 1902, 1911); bere is only found the chitinous crust; but it differs considerably from the crust found 
in Hydractinia carnca., and, on the contrary, wholly agrees with Hydractinia Sarsii (Tab. I Fig. 12). 
iMually also West Greenland (Godthaab) has to be added to the localities where the .species has 
been found (Text-fig. M). 



Hydractinia echinata (Fleming) van Beneden. 
1828 Alcyonium cchinatiivi, Fleming, A History of British Animals, p. 517. 
1841 Hydractinic, van Beneden, Recherches snr la structure de I'ocuf dans un uou\'eau . 

Polyi)e (genre Hydractinie), p. 89. 
1909 Hydractinia nionocarpa pars, Broch, Die Hydroiden der arktischen Meere, j). 199. 



oenre de 



HYDROIDA 



47 



The reptaut stolons are covered 1)\- a continuous cliitinous coenosarc, whose surface is studded 
with small prickles, among which occur larger chitinous spines about 1.5 mm. high, provided with lon- 
gitudinal rows of more or less regular small teeth. The large spines now and then show a tendency 
to divide at the apex. The polyps are up to 4 mm. long, whiti.sh or faintly reddish, with 20—30 
tentacles in a dense whorl below the oral portion. The tentacles form a belt which appears double 
because of alternating displacement. vSpiralzooids without tentacles occur along the margin of 
the colony. 

The gonopliores are cryptomcdusoid, placed, to a number of 3 or 6, round reduced poly])s with 
rudimentar\- tentacles. 

Material : 

Greenland: Upernivik, depth 80 — 90 fathoms without particular data, from a cod's stomach. 
Skagerrak: the channel near Viuga (I5ohuslan), depth 50 fath. 

Hydractiiiia cchiiiata in its large chitinous skeleton-spines (Tab. I Fig. 9 and 10) has a very 
typical armour impeding a confusion with other northern species. It is an Atlantic-boreal species, 
showing a great power of enduring both high and low temperatures. It occurs very frequently in 
the North Sea, along the coasts of Crreat Britain and Ireland, goes to the south as far as into the 
Mediterranean, and is also found on the east coast of North America. The species belongs to the 
litoral region and almost always goes together with Eitpagiirus Beriihardus^ on whose house it settles. 
When we consider the distribution of the species along both sides of the northern Atlantic, we must wonder 
that it has not yet been observed at the Faroe Islands, and that only a single specimen has been met 




Text-fig. N. The occurrence of Hydractwia echinata in the Northern Atlantic. 
(The hatched parties denote according to Htterature a scattered allthongh common occurence). 



48 



HYDROIDA 



with at Iceland. This specimen which was found on the north side of the island, was originally 
recorded by Winther (1880), and has afterwards been revised by Saemundsson (1902). It is a pecu- 
liarity of the specimen that it is seated on the operculum of a Balamis Hammcri, and not on the 
house of the Bernhardus crab. The .species has been recorded once in the Arctic water-layers near Jan 
Mayen (v. Lor en z 1886). In a previous work (1909) I gave utterance to the supposition that the 
variety recorded bv Levin sen (1892) had probably to be referred to the high-arctic species Hydrac- 
tinia vwnocarpa A 11 man. An examination of the specimens mentioned, however, shows that this suppo- 
sition is wrong. The specimens are unquestionable Hydractinia cchinafa with skeleton strongly deve- 
loped. One of the specimens is distinguished by being attached to the shell of a living Buccinum 
hydrophanHvi. The species, thus, proves able to occur now anil then under wholly high-arctic conditions. 

Hydractinia carica Bergh. 
1887 Hydractinia carica, Bergh, Goplepolyper fra Karahavet, p. 3, Taf. 28, Fig. i. 
1899 — niiuuta, Bonnevie, Norske Nordhavs-Expedition, p. 48, Tab. I, Fig. 3. 

The reptant stolons are covered by a chitinous layer of coenosarc, without small prides, but 
bearing here and there vigorous spines, singly placed and up to 0.5 mm. high, conical with rounded 
apex. The polyps attain a length of 2 mm., and have 10 — 14 rather vigorous tentacles placed in a 
single whorl below the oral portion. Spiralzooids are not traceable. 

The gonophores are cryptomedusoid, jjlaced, to a number of 3—6, round polyps almost wholly 
atrophied, forming, if anything, only a short stalk, or showing rudiments of tentacles slightly indicated. 

Material : 

The Kara Sea: Petuchoff.skoi vSchar depth 7 fath. (the original specimen described by Bergh 1887). 

An examination of the original specimen, determined by Bergh, shows with full certainty 
that it is the same species that has afterwards been described by Bonnevie (1899) by the name of 
Hydractinia tniuuta. The diagnoses, however, when compared, will show some points of difference. 
Bonnevie does not mention the .skeleton-formations at all while on the other hand, the statements 
of Bergh convey the impression of a greater resemblance to Hydractinia cchinata than it really bears. 
Hydractinia carica lacks the small prickles found in the species last mentioned, and more vigorous spines 
also occur rather scarcely; the latter (Tab. I, Fig. 11) are smooth and more conically tapering than those 
of Hydractinia Sarsi. The main difference, however, between the diagnosis of Bonnevie and that 
of Bergh is implied in the mention of the blastostyles. Bergh states in his diagno.sis "Sporosacs 
borne on very short, rudimentary hydrants, without or with very few (i — 4) tentacles", while in the 
diagnosis of Bonnevie we find "Fixed gonoiDhores without radial canals, from 3 to 5 in circle round 
. tlie inconspicuous blastostyle.s", and in her .short comment Bonnevie further states that the species 
is distinguished for "the complete atrophy of the gonophore-bearing hydranths". The specimens deter- 
mined by Bergh show a great varying as to the development of the fertile polyp; it may, as he tells 
us, have 1—4 tentacles; but they are a great deal more reduced than is apparent from his pictures, 
and agree better with the drawings published by Jaderholm (1909, PI. 2, Fig. 10 — 11). However, 



ttVDROlDA .A 



there are in the colonies also numerous blastostyles, which arc wholly devoid of rudiments of tentacles 
and accordingly only forming a stalk in the same way as is indicated by the diagnosis of Bonnevie. 
Rut there always occurs a small polyp, and a "complete atrophy" of the polyp is in no case demon- 
strable; nor is it obvious from the imperfect figure of Bonnevie (1899, Tab. I, Fig. 3). — The great 
variation of the blastostyles of the original specimens dcterniined bv Bergh, shows us that the 
species stated by Bonnevie may be founded on a colony where the blastostyles carrying tentacles 
were reduced to a minimum in number. But this does not give sufficient reason for maintaining it 
as a peculiar species beside Ilydracfijiia carica. 

Hydractiiiia carica is an Arctic litoral species, which, in boreal waters, proves able to penetrate 
along the West coast of Norway as far as Bergen (Text-fig. j\I). It has been found elsewhere only 
in high arctic regions, in the Kara Sea, in the Murman Sea, and at Spitzbergcn. It has also been re- 
corded by Jaderholm (1909) from Davis Strait. 



Gen. Bougainvillia Lesson. 

Upright colonies with branched hydrocauli clothed with a ])erisarc. The polyps are fusi- 
form with the tentacles placed in a whorl belovi' the conically pointed oral portion. The polyps are 
naked without the slightest attempt at formation of pseudohydrotheca romid their proximal portion. 
The gonophores are placed on the stems of polyps fully developed or reduced (blastostyles). In the 
latter case, the unbranched polyp stem will sometimes rise from the hydrorhiza instead of from the 
hydrocaulus. 

A closer inquiry into the distinguishing characters and their sxstemalic value, shows us that there 
is no reason to distribute the species of Boiigaiiivillia on the three genera. Boiiga iu'i'illia, Dicoryne^a.wA Hctero- 
cordylc. Sufficient cause for distinguishing between Boiigaiiivil/ia and the two other genera is not at all 
given by the fact that the former has medusoid gonophores, while the two other genera liave styloid go- 
nophores. In mentioning the genera earlier treated, I have sufficiently explained the insignificance of this 
criterion as to classification. Then remains the other distinguishing mark that the gonoi^hores of Bougain- 
villia develop on the stems of some fullgrown polyps, while in Dicorync and Ilcterocordyk they are devel- 
oped on the stems of reduced polyps (blastostyles). The genus Hydraciinia shows us a full parallel to this 
condition of things. But because of the many and close connecting links between one extreme and 
the other, it has been agreed that the stronger and weaker .specializing into nourishing polyps and 
blastostyles cannot be employed as a generic character. When, on the other hand, this has been done 
with BoiigaiiivilUa and Dicoryne and Hetrrocordyh; the onl\- reason must be that, between the few 
species known of these genera, most of the links occurring in Ilydractinia are wanting. This lack, 
in fact, is not a sufficient rea.son to elevate, in one case, the character to an importance which is denied 
in another case, even within the same family. It is not right to base the genera Boiigainvillia, Di- 
coryne and Hctcrocordyh- on characters that must be used with discretion as specific characters 
in Hydractiiiia. Further, as to the distinguishing mark between Dicorync and Hetcrocordyle, it is 
still more diminutive. Hctcrocordylc conyhcari All man, the only species known of the genus, is so like 

The Inoolf-Expediiion. V. 6. 



50 



HYDROIDA 



Dicoryne co7iferta (Alder) as to confusion, and the two species have probably more than once been mis- 
taken for one another. Both the species have styloid gonophores; but in Heterocordyle they are ses- 
sile, while in Dicorync^ when ripening, they assume cilia all over, develop two tentacles, and break 
away. This is, unquestionably, a phenomenon of mere biological adaptation and cannot be recognized 
as sufficient for distinction of genera as long as it is not accompanied by a thorough change of the 
organization of the sterile parts of the colon)-. It is evident that Dicorync and IJelcrocordylc must be 
drawn together into one genus, and moreover that this genus must be united with Bongaijivillia. 




Text-fig. O. The habitat of Ikmgainvillia conferta in the Northern Atlantic. 
(In the hatched regions the litterature denotes the occurence of the species without strict locahties). 



Bougainvillia conferta (Alder). 

1856 Eiidrmiriiiiii coii/i-rfnii/^ Alder, A Notice of Some New Genera and Species of British Hydroid 

Zoophytes, p. 354, pi. 12, fig. 5-8. 

The colonies attain a height of up to 15 mm., and exhibit a rigid appearance. They have a 
distinct main stem witli short side-brauclies. The perisarc is vigorously developed and dark brown- 
coloured. The small fusiform polyp attains a length of al)out 0.5 mm.; it wears about 16 tentacles in 
a single whorl below tiie oral conically pointed portion. 

The gonophores are stvloid and Ijreak away. When ripening, they assume a peculiar oviform 
shape, develop two filiform tentacles, and \n\i on a complete suit of cilia all over. The gonophores 
are seated, gathered in a belt, somewhat t^elow the apex of blastostyles, which arise from the hydro- 
caulus or, in smaller numbers, from the hydrorhiza. The blastostyles show no indication of tentacles. 



HYDROIDA ci 



Material: 

Iceland: Talkiiafjord (without particular data). 

Reydarfjord, depth 163 metres. 
The Faroe Islands (without particidar data). 

Bougaiiivillia (W^/^vA? is a southern-Ijoreal species penetrating- as far as into the Mediterranean; 
towards the north it goes, along the coast of Norway, only as far as Lofoten. It has been recorded several 
times from Iceland, in the warmer water-layers along the west- and south-coasts of the island, but it 
has not yet been pointed out at Greenland. As a new locality must be added the Faroe Island.s. The 
species is indigenous to the literal region. 



Gen. Perigonimus M Sars. 

The hydranth stems rise immediately from the reptant stolons, or there are formed upright 
rhizocaulomes bearing the pohps. The pohp stems are sometimes divided into a coujjIc of branches; 
still liydrocaulns, properly speaking, cannot be recorded. The polyps are fusiform, with the tentacles 
placed in a whorl below the conically jjointed oral portion; below the tentacle whorl they are sur- 
rounded h\ delicate pseudoh\'drothecae, superiorly connected with the ectoderm of the hydranth, and 
inferiorly passing into the chitiuous perisarc of the stem. The stinging cells show attempts at being 
arranged in transverse belts on the tentacles. The gonophores are jjlaced singh- on the stolons or on 
the hydranth stems, most freqnentl)' attached to the latter by a short stalk. 

The distinguishing marks between Prrigouimus and Bougniiivillia. indeed, seem to be so in- 
significant that the conclusion might be obvious that both genera should be united into one. The 
Perigoi/iiiiiis polyp, when wholly extended, is very easih' mistaken for a Bougainvillia. However, there 
is an essential difference between the two genera which necessitates a separation. Their medusae 
even belong to different families, the Bougai 1171 ill i(i-\\\&A\\s^^ being typical Margeiidae, wliile Perigom- 
iiiits gives rise to Tiaridae (see Hartlanb 1913). As far as the nurse jfolyp is concerned, we must 
notice the difference existing between the wholly naked Bougaiiivillia-'^o\\\) and the hydranth covered 
with pseudohydrotheca of the Pcrigoiiiiniis-\io\\'^. The psendohydrotheca has been pointed out b\- sev- 
eral authors and has been emphasized as generic character particularly by Broch (1911). A closer 
inquiry into this formation has been made by Hadzi(i9i3, 1914), who has studied it most thoroughly 
in the .Adriatic species, Pcrigoniiiins Corii Hadzi and Pirigoitiiuus Georginae Hadzi; the latter spe- 
cies is very nearly related to Pcrigoniiiiits rfpciis (Wright). Hadzi points out that Pcrigotiimns is 
provided with a sort of hydrotheca, the essential substance of which is jellied and accordingly not 
entirely parallel with the hydrotheca of the thecaphore hydroid.s. For this jellied polyp case, which 
is, in its outer margin, connected with the ectoderm of the polyp, I, therefore, employ the denomina- 
tion of "pseudohydrotheca", earlier emplo_\-ed for the chitinons false hydrothecae of Clatlirozoon. In the 
case of Chlathrozoon, however, the formation seems to be quite different, and the denomination, ou 
that account, rather misleading; indeed, we had better employ the term of "false hydrothecae". Hadzi 



__ HYDROIDA 

5^ 



calls our attention to the interesting fact that the polyps are basally attached to the psendohydrotheca 
by a whorl of small chitinons bodies similar to that met with in Haleciidae, Pluuiulariidac, La/oeidac, 
and Cainpaiiulariidac ; they actnalh- attach the supporting lamella to the polyp case. Systematically, 
however, hardly any particular ini]H)rtance can be attached to this character. The chitinons bodies 
occur on the passage from the psendohydrotheca to the hard periderm of the stem. Also the periderm 
of the stem has, in most species of Pcrigouiiiius a jellied cover, to which a lot of foreign bodies fasten 
themselves so as to give the colony a foul appearance. 

The stinging cells in the tentacles of the Pfrigoniwiis-^pe:c\es show attempts at an arrange- 
ment by belts. But it is not here so pronounced as in the Eudendriidae and the thecaphore hydroids. 
This criterion, together with the psendohydrotheca, suggests that Perigotiimus must be more nearly 
related to the thecaphore hydroids than most other athecate hydroids. 



Perigonimus repens (Wright) AUman. 

1857 Eiidoidrimn repots, Wright, Observations on British Zoophytes, p. 84, pi. 82, fig. 8—9. 
1864 Pcrigoiiitnus — , AUman, On the Construction and lyimitation of Genera among the Hy- 

droida, p. 365. 
nee 191 1 — — , Broch, Fauna droebachiensi.s, p. 14. 

From the reptant stolons proceed thin polyp stem.s, up to 5 mm. long, more rarely dichotomi- 
cally divided so as to bear two polyps. The polyps are about 0.5 ram. long, broadly fusiform, with 
4—12 tentacles placed in a whorl, and surrounded below the tentacles by a thin jellied psendohydro- 
theca, which is sometimes hardly observable. The polyp stems are wholly without rings, and all but 
without wrinkles, and provided with a dark-coloured, but thin perisarc, which, on account of bottom 
particles appendant, convey the impression of being granulous. 

The gonophores are de\'eloped into free medusae; when breaking away, they have two ten- 
tacles and a well-developed, solid umbrella. The gonophores are borne individually on stems 0.2—0.3 
mm. long, proceeding from the h)dranth stems; on one hydranth stem is generally developed one 
gonophore at a time, sometimes a couple of gonophores simultaneously. 

Material : 

The Faroe Islands, vSiirvaag. Depth 14 — 16'/2 fatli. (on Nncula tntclrus). 

Certainly it is not this species that is delineated and described b)' the name of Pcrigoiiitnns 
rrpciis in Fauna Droebachiensis (Broch 1911). A comparison with the excellent drawings of the 
species with Jadcrholm (1909, Taf. I, Fig. 15 — 16), at once shows us the difference. The species 
described and delineated from the Kristianiafjord has a stiff and robust structure; its perisarc is .solid 
and the colonies are open rhizocaulome formations; most probabh- the specimens in question should 
have been referred to Perigonimus iiniscoides M. Sars. Pcrigouinnis rcpciis, on the other hand, has 
thin closely set, irregularly curved polyp stems. Besides, the colonies from the Kristianiafjord bear on 
the hydranth stems numerous gonophores without stalks, while the few gonophores of Perigotiiitnis 
repens are borne on distinct small stalks covered with perisarc. 



HYDROIDA 



53 



Pcrigoiiiiiiiis rcpois is a southern species which penetrates into our seas. It has been recorded 
from tlie Mediterranean and the west coast of France, and occurs frequenth' in the sea round Great 
Britain and Ireland. Already in the North Sea its occtirrencc is more straggling. In the Danisli 
waters and along the coast of Bohuslan it is still rather frequent. On the coast of Norway it is not 
uufrequently met with in the Trondhjemfjord, where the fauna, on the whole, bears a southern char- 
acter. But only once it has been fouud farther to the north, at I^ofoteu. Siemundsson (1911) re- 
cords several questionable specimens from the west and the north of Iceland. But tliese localities 
have to be confirmed. As a new locality must now be added the Faroe Islaud.s. The species belongs 
to the literal region. 




200 m. 



6 00 m 



,1000 m. 



2 000 m- 



Te.\t-fig. P. The distribution of rcrigoniniiis ivpcns in the Northern Atlantic (o locahties needing further confir- 
mation. — In the hatclied region the litterature denotes a scattered although common occurence of the species). 



Perlgonimus abyssi G. O. Sar.s. 
1874 Perigonimus abyssi, G. O. Sars, Bidrag til Kundskaben om Norges Hydroider, p. 96, pi. 5, Fig. 27—30. 
191 1 — sp., Kramp, Danmarks-Ekspeditionen til Gronlauds Nordostkyst, p. 363. 

From the reptant stolons proceed unbrauched polyp stems, which attain a length of 1.5 mm. 
The polyps are about 0.5 mm. long, Ijroadly fusiform, bearing 5—8, usuall\- 7 tentacles in a whorl. 
Below the tentacles the polyp is smrounded by a rather \-igorous, wide, jellied pseudohydrotheca, wliich 
is, however, often hardh- visible on the polyp wholly extended. The polyp stems are irregularly and 
strongly wrinkled, and have a dark-coloured, vigorous perisarc. 

The gonophores are developed into free medusae, having, when deliberated, a vigorously 
developed umbrella and four tentacles. The gonophores are developed on the polyp stems, to which 
thev are attached by a very short stalk. On the polyp stem arise one or two gonophores. 



54 



HYDROIDA 



Material : 

Greenland, Egedesminde (on Lcpcfa cocca). 

The species has been fonnd chiefly along the west coast of Scandinavia. It is likely to occnr 
ninch more frequently than might be believed from the scattered data. On account of its small 
dimensions, and as, besides, it prefers settling on living, smaller molluscs, it too often escapes the 
attention of the investigators of hydroids. Perigouiiints abyssi has been found at Bohusljin and 
on the west coast of Norway, from Stavanger as far as the Trondhjemfjord, at the depth of loo 
—600 metres. On the north side of Beeren Island it has been met with at the depth of 165 




Text-fij;. Q The finds of Pcrigoniiniis abyssi ill the Northern Atlantic. 

metres (Bonne vie 1899). In Arctic regions it may occur in considerably shallower waters. Thus the 
German expedition to Spitzbergen in 1898 found the species in the Storfjord at the depth of between 
o and 10 metres (Broch 1909), and certainly it is the same species that is recorded by Kramp (1911), 
by the name of Pcrigonimns sp., from the depth of 20 — 40 metres at a couple of stations of the "Dan- 
mark" Expedition. To the localities previously recorded must now also be added the west coast of 
Greenland near Egedesminde. — According to the data in hand, the species must be characterized as 
Arctic and boreal (Text-fig. Q). 



Perigonimus roseus (M. Sars) Bonnevie. 
1874 RliizoraghuH rosczim, M. Sars in: G. O. Sars, Bidrag til Kundskaben om Norges H>droider, p. 96. 
1892 Garveia groenlandica^ Levinsen, Meduser, Ctenophorer eg H},droider fra Gronlands Vestkyst, p. 13. 
1898 Perigonimus roseus^ Bonnevie, Neue norwegische Hydroiden. 
191 1 Garveia groenlandica, Kramp, Danmark-Ekspeditionen til Gronlands Nordostkyst, p. 363, pi. XXV, fig. 6. 



HYDROIDA 



55 



From the reptant stolons proceed polyp stems up to 12 nmi. long, generally nnbranched; more 
rarely 2—4 polyp stems proceed from a common trunk, 1—2 mm. high. The polyps attain a lengtli 
of 0.7 mm., and are fusiform, with 6 — 12 tentacles placed in a whorl. Below the tentacles the polyp 
is surrounded by a pseudohydrotheca, which it is very difficult to observe on the pohp when wliollv 
extended. In general it is jellied and vigoron.sly developed. The polyp stems are, particularly in their 
pro.ximal part, irregularly wrinkled. 

The very large gonophores show no medusoid structure; they are attached to the reptant sto- 
lons by a short stem. 

Material: 

Greenland (Lille Hellefiskebanke) (the original specimen of Garvcia groenlandica Levinsen). 

An examination of the original specimen of Garvcia groenlandica shows no difference at all 
from Norwegian specimens of Pfrigo)iiinus roseits. The species are no doubt identical. If we compare 
Kramp's drawing of Garvcia groenlandica (1911, pi. XXV, fig. 6) with Jiiderhohn's figure of Pc- 
rigoniniHS roscus (1909, Taf. Ill, Fig. 7), there ma}-, at the first glance, seem to be some jjoints of 
difference. Thus the stems of the siDccimen mentioned by Kramp are much shorter. But this character 
proves of little significance if we compare the specimen with a larger colony, where, as a matter of 
fact, the length of the polyj) stems varies greatly. A greater stress might, on the other hand, be laid 
on the apparently great difference between the pseudohydrothecae as represented in the two figures. 
However, much depends on the contraction of the polyps and on the state of preservation, as is plainly 
to be seen bv an inquir\' into a larger material. I have several times had the opportunit\- of observ- 




zoom. 600m. looom. . zooom. 

Text-fig. R. The occurence of Perigonimiis roseia in the Nortliern Atlantic. 
(In the hatched region the occurence according to the Htterature is coiunion allthough scattered). 



56 



HYDROIDA 



ino-, in larger colonies of Perigoniiiiiis, individuals with pseudohydrotliecae bulging even more loosely 
round the shrunken and contracted polyps than that rendered in Kramp's drawing, while, at the 
same time, in extended polyps in the same colony, a superficial view fails to notice the presence of 
this formation (Broch 1911, fig. 12). The intermediate state represented by Jaderholm is the com- 
monest observed in preserved colonies. Still one point of difference might seem to remain, the chiti- 
nous cup in which the gonophore, in Garvcia groailaiidica, is resting when it is about to empty its 
ripe contents. This cup, or rather this remnant of the flayed-off external periderm cover of the gono- 
phore, is, however, frequently observed also in the female gonophores of typical Perigoninius roscus, 
in which hitherto no particular importance has been attached to this character. Accordingl)', we have 
to include Garveia groenlandica as a synonyme under Pcrigoniiiius rosciis. 

The chief occurrence of the species is attached to the middle and the lower parts of the litoral 
region of the boreal waters. It occurs rather frequently from Bohuslan as far as Lofoten, generally 
attached to stalks of Tiibularia iiichvisa. However the species also penetrates far into Arctic waters, 
and has been recorded from the White Sea and as far to the north as Nova Zembla. It has previ- 
ously been recorded from Greenland (Jaderholm 1909), where now also Lille Hellefiskebanke, Fiske- 
nes (West Greenland), and Danmarks Havn (East Greenland) have to be added to its localities 
(Text-fig. R). 



Family Eudendriidae. 

Hydroids forming colonies, the polyps of which are provided with a single whorl of filiform 
tentacles. The proboscis is capitate, placed with a narrow base on the broad polyp body above the 
tentacle whorl; the stinging cells of the tentacles are small and rodshaped. Also larger stinging cells, 
narrowly oval, occur, particularly in the specific stinging organs of the polyp. The stinging cells of the 
tentacles are arranged in very distinctive transverse belts. The polyps are wholly naked. The endoderm 
of the polyp is differentiated into two portions, an oral portion, consisting of small-nucleated, indifferent 
cells, among which occur some mucous gland cells, and the proper gastral portion. The limit is formed 
l)v the tentacle whorl. The tentacles lack a central cavity. The colonies have no calcareous skeleton. 

Nearly all investigators of hydroids have distinguished the Kiidciuh-iidac as a familj- of their 
own. To this Levinsen (1892) forms an exception, considering the arrangement of the tentacles in 
a single whorl round the polyp as indicative of so near a relationship to the Boitgainvilliidac that he 
unites tlie two families into one. However, the Eiidii/driidar, in their structure of the polyps, show, 
as compared to other athecate h}droids, such peculiarities that we are forced to distinguish them as 
a family of their own. In the first place are obvious the broad structure of the polyp body and the 
capitate proboscis, placed with a narrow base above the well defined tentacle portion. In this cha- 
racter the polyps bear a strongly marked reseml^lance to the thecaphore Cainpainilariidae. This like- 
ness is the more interesting because, in the more delicate structure of the polyp of the Eudeiidriidai\ 
several points of resemblance to the thecaphore hydroids are demonstrable. Thus the stinging cells of 
the tentacles of Eudendriidae^ as well as those of the thecaijliore hydroids, are arranged in well defined 



HYDROIDA ^7 



transverse belts. This peculiarity we find slightly indicated even in sonic BovgainviUiidac. But onlv 
in the Etidendriidac it has become a character plainly distinctive. Further, the endoderm in the well 
defined hypostome shows the same structure as in the thecaphore liydroids, and is more strongly differ- 
entiated than in the Boiigai)iviUiid(u\ the indifferent cells having gained the ascendency, and the number 
of the mucous gland cells having been reduced to a miniiuum. Whether these peculiarities are indic- 
ative of a nearer relationship between the Endoidyiidac and the thecaphore hydroids, is a question 
which it would here be out of place to enlarge upon. 

The Etidendriidac^ with their frequently dimorphic development of the stinging cells, also pre- 
sent a parallel to the Stylastcridac. Besides the small rodformed stinging cells characteristic of all 
Fili/cra, we also find in several species larger narrowly oval ones, bearing a strong resemblance to 
those of the Stylastcridac. The latter are large, but of the same shape as the small stinging cells of 
JSIyriotlirla. We probably here face a phenomenon of con\ergency, the reason of which, however, at 
the present stage of our knowledge of the biology of the Coelenterata, we cannot account for with 
any certainty. Wherever the larger stinging cells occur in the Endciidriidac they are accumulated in 
particular stinging organs. 

Eudendrium Ehrenberg. 

Upright colonies with Ijrauchcd li\drocaulus. The jjolyps are broad and distincth- set off from 
the stem, which is covered with a vigorous chitinous perisarc. The JJoh-p has a single whorl of fili- 
form tentacles. Above the tentacle whorl the polyp is suddenly tapering and ends into a capitate or 
trurapetshaiDed proboscis, which is seated, with a narrow base, above the tentacle whorl. The gono- 
phores are developed on normal or reduced polyps, or placed singly on the branches. 

Kiilin (1913, p. 48) states that the polyp tentacles of Eudrudriniu "nach einander vorsprossen 
und dadurch sich als Angehorige verschiedeuer Wirtel zu erkenuen geben". Later on (1. c. p. 247) he 
again mentions this peculiarity as a refutatory argument against the adoption of a nearer relationship 
to the thecaphore hydroids; in the passage last cpioted he apparently bases his opinion essentially on All- 
man (1872). A closer inquiry, on new material, gave no hold to the statement of Allmau and Kiih n that 
the tentacles should appear successively. In the numerous colonies examined of Eudendrium raiucjcin 
(Pallas) and Eudendrium WrigJifi Hartlaub it could be ascertained that all the tentacles appear 
.simultaneously. This suggests that the observations of Allmau may rather depend on accidental cir- 
cumstances, and that no special importance must be attached to them as reminiscences of manyrowed 
tentacle-whorls of the ancestors or as proofs of a nearer or remoter relationship to the Bougainvil- 
liidae or to the thecaphore h)droids. 



Eudendrium rameum (Pallas) Thompson. 

1766 Tubularia raiiiea, Pallas, Elenchus zoophytorum, p. 83. 

1844 Eudendrium rameum., Thompson, Report on the Fauna of Ireland, j). 283. 

1887 — ramosum, Bergh, Karahavets goplepolyper, p. 332. 

The Ingolf-Expcdition. V. 6. 



58 



HYDROIDA 



1908 Eudendrhiiii cariami, Jaderholm, Die Hydroiden des Sibirisclien Eismeeres, p. 5, Taf. I, Fig. 4, 

Taf. II, Fig. I. 
1911 — rigidum? + Eiidciidriion ramosioii, Sfenuuidssoii, Bidrag til Kundskaben om de is- 

landske Hydroider, p. 74—75. 

Tlie strongly and irregularly branched colonies have a fascicled main stem, and attain a height 
of 200 nnn. The small branches are annulated immediately above their rise from the mother branch, 
but are elsewhere smooth. The polyps have about 20 tentacles. There is no particularly developed 
ring of stinging cells round the tentacles or the polyp body. The colonies have no particular sting- 
ing organs. 

The gonophores are styloid. The male gonophores Have 2—4 chambers and are seated round 
the base of fully developed polyps. The female gonophores are pear-shaped, and are borne on the 
bodies or the hydrocauli of polyps that ma>' either be fully developed, or somewhat smaller than the 
sterile polyps, or entirely reduced. The spadix is unbranched. 

Material: 

"Ingolf" St. 21. 58°oi' N. lat. 44°45' long W. Depth 1330 fath. 2°4 C. 

- - 31. 66°35' - - 55°54' - - - 88 - i°6 - 

- - 44. 6i°42' - - 9°36' - - _ 545 _ 4°8 - 

Greenland : Davis Strait Depth 80—100 fath. 

Henry Land, East Greenland — 20 — 

Cape Tobin — 57 — 

Iceland: 6 miles west of Iceland — 22 — 

Stykkisholm — 20—30 — 

Faxebugt, 16 miles N.E. of Akranes {^'•Eudciidriiiin^ rai/iosuiir) — 26 — 30 — 

Vestman Islands {^'•JCndciidn'/ii/i rigid it m .^") — 30 — 

The Faroe Islands: Stokken 2 engl. miles S 22 E — 55 — 

"Thor" 6i°i5' N. lat. 9°35' W. long. — 872 m. 

"Diana" 6i°4o' - - 7°4o' - — — i35 ^^it'i- 

Store Fiskebanke (Large fishing-bank) 57°7' - - 2°4o' E. — — 37 — 
The Kara Sea, "Djimphna". 

This common northern species has, no doubt, frequently been confused with the southern spe- 
cies Eudendrium rainosiini (lyin.), which, in fact, is rather rare in our northern seas. Assuredly enough, 
nearly all the statements of the occurrence of the last-mentioned species in Arctic waters, are to be 
regarded as referring to specimens of Eiidoidriitiii raiiirnin, the appearance of which varies greatly 
indeed. It has already been jiointed out by Kranip (1911) that the species Eudendritim cariciiiii from 
the Russian polar expedition, described by Jaderholm (1908), is, in fact, founded on specimens of 
Rudendriinn ramcuju. Surely enough, it is the same species which is recorded by Bergii (1887) now 
as Eudendriian rameum and Eudendritim ramosuvi^ now as Eudcndritun sp. 

The species has a circumpolar distribution, and appears, from the statements of literature, to be a 



HYDROIDA 



59 




2ooom. 



Text-fig. S. The haliitat of Endendrium ramc-nm in the Northern Atlantic. 

jDerfect cosmopolite. It occurs frequently everywhere in the middle and deeper parts of the litoral region 
of the northern seas (Text-fig. S), and may, exceptionally, as in the "Ingolf st. 21, also penetrate far 
down into the abyssal region. 



Eudendrium ramosum (Linne) Ehrenberg. 
1758 Tubidaria raiiiosa^ Linne, Systema naturae, ed. X, p. 804. 

1834 Fjtdt'iidriuiii raiiiosujii^ Ehrenberg, Beitrage zur physiologischcn Kenntnisse der Coralleiithiere, 

p. 296. 
nee 1887 — — , Bergh, Karahavets Goplepolyper, p. 332. 

nee 191 1 — — , Ssemundsson, Bidrag til Kundskaben om de islandske Hydroider, p. 74. 

The strongly branched colonies show an almost quite regular, alternating arrangement of 
the small branches. The main stem is fascicled. The small branches are annulated above their rise 
from the mother branch, but are elsewhere quite smooth. The polyps have about 20 tentacles. The 
stinging cells are not accumulated in any particular main ring round the tentacles or the polyp body. 
The colony has no particular stinging organs. 

The gonophores are styloid. The male gonophores have 2—3 chambers and are seated round 
entirely atrophied polyps with short ]i)drocauli. The female gonophores are pear-shaped and borne 
on the bodies or on the stems of poljps which are either fully developed or somewhat reduced as 
compared to the sterile polyps. The .spadix is unbranched. 

Material : 

Southeastern Iceland : (Horring) 1S98. — Depth 52—49 fath. 

8» 



6o HYDROIDA 



The species Eudendrium ramosuni (Pallas), Eudeudrmm rameum (Pallas), and Eudendrium race- 
viosum (Cavolini) are verj' nearly related to each other, and sterile colonies of the three species are often 
hardly distingiiished with certainty. While in Eudendrium rameum the male gonophores are borne on 
polyps fully developed, they are seated, in Eudendrhim ramosiiin and Eudendrium racemosjDii round polyps 
wholly reduced. This conformity of the two last-mentioned species, the homogeneous structure of their 
colonies, and several other features common to them, which struck me during my inquiry into the Adriatic 
hydroids (1912), really led me to consider, though witli some doubt, Endeiidriiitn. raccmosuvi as a synonyme 
of Eudeiidriitiii ramosiim. This supposition, however, is hardly right. By the liberality of Dr. C. Leh n ho- 
fer at Innsbruck I have afterwards had the opportunity of examining more closely unquestionable colo- 
nies of Eudendrium raccmosicm from Triest, and of recognizing in these the characteristic criteria distin- 
guishing this species from Eudendrium rantosum. Occasionally are found developed in the polyp of Fai- 
dendrium racemosum peculiar organs which are not traceable in other species of the genus, and which, like 
analogous organs in other hydroids, have to be designated as "nematophores" (cp. Weismann 18S2). 
Elsewhere the presence or the absence of these formations is looked upon as a generic character among 
the lu'droids. But tliis view is here hardly justifiable, as in Endciidriti))i racciiiosum the nematophores occur 
quite irregularly and are rather rare; in some colonies they are even entirely wanting, and such colonies, 
when sterile, or when only male indi\idua]s occur, cannot be distinguished with certainty from Eudendrium 
ramosuni. — Tlie other distinguishing mark Isetween the two species is the spadix of the female gono- 
phores. While, according to the descriptions in hand, the spadix of Etidendrium ramosuin is unbranched, 
that of Eudendriuin racemosum is, on the contrary, bifurcate or divided into three branches, embracing 
the ovum like a claw (s. Broch 1914 Stylasteridae p. 24, Text-fig. I) I regret that I have not succeeded 
in getting hold of fertile female colonies of Etidendrium ramosum, so as to be unable to give a draw- 
ing, from new material, of the female gonophore of this species. 

From the statements above it is clear that Endendriitm ramosum has most probably been 
several times confused with Eudendrium racemosum. On the other hand, as I have earlier pointed 
out, a confusion with Eudendrium rameum.^ particularly from the northern seas has also often taken 
place, and tlie geographical data presently in hand as to Etidendrium ramosum are, therefore, of most 
questionable value. A closer inquiry into the colonies from Faxebugt (Iceland) recorded by S ic m u n d ,s- 
son (1911) as Eudendrium ramosum, shows tliat we here realh- face typical Eudendrium rameum. 
However, the single specimen of the species which is in hand, shows us that in warmer layers of 
the Atlantic it may occur as far to the north as Iceland. The occurrence of the species in tlie northern 
Atlantic regions, however, has yet to Ije more closely accomited for. 

Eudendrium Wrighti Hartlanb. 
1859 Eudendrium arbuscula, Wright, Observations on British Zoophytes, p. 113, pi. 9, fig. 5—6. 
1905 ~ Wrighti, Hartlanb, Die Ilydroidcn der magalhaensischen Region, p. 547. 

The strongly and irregularly branched colonies have a fascicled main stem, and attain a height 
of 60 mm. Tlie small branches are annidated above their rise from the mother branch, but are else- 
where smooth. The jjolyps have a large numljer of tentacles. Tlie tentacles have no particularly 



HYDROIDA 



6i 



distinct main ring of nematocysts. On tlie other hand, there is round the pol\p body, at its base, a 
distinctive girdle of large stinging cells. Otherwise, the colony has no particular stinging organs. 

The gonophores are styloid. The male gonophores have two chambers with a well marked 
accumulation of stinging cells distally, and are densely clustered on short stems perpendicularly 
jDlaced on the trunk. Female gonophores are unknown. 

Material: 

The Faroe Islands: Trangisvaag, on roots of Lainiiiaria. 

The species was first described by Wright (1859) by the name of Riidcndrhun arhiiscula from 
the Firth of F^orth. However, another Eudcudrium had been previously described by d'Orbigny 




200 ffi. _«..---6oom. .^..,._.«.._.IOOO m. 20oom. 

Text- fig. T. The occurence of Eiidcndrium h'lighti • and Endeinhuim aniiulattim ▲ in the Northern Atlantic. 
(The vothed coastal parties denote a scattered occurence of Eiuleittium Wright i according to the litterature). 

(1839) by the name of Tubularia arbusada from Patagonia, and even though it will be questionable 
whether the species of d'Orbigny can be reidentified, we are no doubt right to follow Hartlaub 
(1905) and abandon the name of arbiiscula for the northern species. Here we, therefore, adopt the 
denomination of Hartlaub, Eudcndriiiiii Wrighfi. 

Eiidciidriuiii Wn'g/ifi \s an absolutely littoral species, the occurence of which seems to be restricted 
to the zone of the Ivaminaria. It occurs quite frequently from Bohuslan as far as towards tlie Trond- 
hjemfjord, and it is peculiar, therefore, that its female gonophores have not yet been pointed out. The 
species is quite common at the British Isles (s. the Text-fig. T), and it has also been recorded from the 
Mediterranean. Eudendriuiu Wright! is, therefore, likely to be characterized as an Atlantic species of 
southern character, which is able to penetrate into the northern seas as far as the Trondhjcmfjord. 
The Faroe Islands have now to be added to the localities where the species has been found. 



g ' HYDROIDA 



Eudendrium annulatum Noimaim. 
1864 Eudendrium anmilatiiiii, Norman, On undescribed British Hydrozoa, Actinozoa, and Polyzoa, p. 

83, Pl- 9. fig- 1—3- 

The strongly and irregnlarl)- branched colonies have a fascicled main stem, and attain a height 
of 100 mm. All the smaller branches are densely annnlated everywhere. The polyps have 16—20 
tentacles. There are no particular accumulations of stinging cells on the tentacles or on the polyp 
body, and the colony has no particidar stinging organs. 

The gouophores are styloid. The male gonophores have one chamber with an accumulation of 
stinging cells distally, and are densely grouped on short stalks perpendicularly placed on the stem. 
The female gonophores have an unbranched spadix and form grape-like clusters round polyps entirely 
atrophied. 

Material : 

Greenland: Sukkertoppen (without particular data). 

Iceland: Vestman Island, on the stems of Tubularia indivisa. 

Eudendrhim aninihiiuiii seems to occur rather sparsel)', but apparently on the whole prefers 
the littoral parts of the boreal seas. However, among the localities of the species are also recorded 
the Cape Verde Islands (Ouelch 1885), and with some doubt Cape Town (Ritchie 1907). On the 
west coasts of Scandinavia the species has been met with here and there from Bohuslan as far as 
Vadso, and it even occurs in the Murman Sea. It has been found near Jan Ma>'en and the Shetlands, 
and specimens occur from the south of Iceland and from West Greenland. 

Eudendrium capillare Alder. 
1856 Eudendrium capillare. Alder, A notice of some new Genera and Species of British Hydroid Zoo- 
phytes, p. 355, pi. 12, fig. 9—12. 

The strongly and irregularly branched colonies have a simple unfascicled main stem, and 
attain a lieight of 30 mm. The branches show a few rings immediately above their rise. But else- 
where they are smooth. Tlie polyps have 20—30 tentacles. There are no particular accumulations of 
stinging cells on the tentacles or on the polyps. The colonies have no particidar stinging organs. 

The gonopliores arc styloid. The male gonophores have two chambers with an accunndation 
of stinging cells distally, and are i)laced in a whorl round entirely atrophied polyps or, more rarely, 
round strongly reduced polyps, tlie stems of which rise from tlie hydrocaulus or the Indrorhiza. The 
female gonophores occur in the same manner; they are pear-shaped with unl)ranched spadix. 

Material: 

Greenland: Store Hellefiskebanke . . . Depth 28 fatli. 

Iceland: Stykkisholm . . . Depth 30 fath. 

The Faroe Islands: between Nolso and Ustntes . . . Depth 100 fath. 

The specimens from the ".Store Hellefiskebanke" offer a great interest, the male gouophores 



HYDROIDA 



63 




. 600 171. 



Text-fig. U. The distribution of Etuhndrium capillaie in the Northern Atlantic. 
(The hatched coastal region indicates a scattered occurence according to the Htterature). 



being borne by diminutive pol)ps. It accordingly appears that the fertile poljjj.s of the species are 
not always wholly atrophied, as has hitherto been generally supposed. 

The distribution of Eiidti/dn'mii capillarc is extremely wide, almost quite cosmopolitan. It very 
frequently occurs in the northern seas (Text-fig. U); however, already in the Norwegian Sea and 
along the west coast of Norway its occurence becomes less frequent, and it does not penetrate very 
far into the Arctic regions. The species belongs to the middle parts of the littoral region. 



LITERATURE 

1. Agassiz, L- (i860 — 1862): Contributions to the Natural History of the United States of America, Second Monograph, 

vol. 3 and 4. Boston. 

2. Alder, J. (1S56): A Notice of Some New Genera and Species of British Hj-droid Zoophj'tes. (Ann. and Mag. of nat. 

Hist. Ser. 2, vol. 18). London. 

3. Allnian, G. J. (1864): Notes on the Hydroida. (Ann. and Mag. of nat. Hist. Ser. 3, vol. 14). London. 

4. — (1S64): On the Construction and Limitation of Genera among the Hydroida. (.\nu. and Mag. of nat. Hist. Ser. 3, 

vol. 13). London. 

5. — (1S72): A Monograph of the Gyninoblastic or Tubularian Hydroids. London. 

6. — (1876): Diagnoses of New Genera and Species of Hydroids. (Journ. Linneaii Soc. (Zoology), vol. 12). London. 

7. — (1877): Report on the Hydroida, Collected during the Exploration of the Gulf .Stream by L. F. de Pourtales. (Mem. 

Mus. Conip. Zool. Harvard College, vol. 5). Cambridge. 

8. Babic, K. (1904): Uebersicht der Hidroidpolypen des adriatischen Meeres. (Glasnih hrv. naravoslovn. drustva, vol. XV). 

Zagreb. 

9. Bedot, M. (1901 — 12): Materiaux pour servir a I'Histoire des Hydro'ides. (Rev. Suisse de Zool. Vol. 9, 13, iS and 20). 

Geneve. 
10. Behner, A. (1914): Beitrag zur Kenntnis der Hydroniedusen. (Zeitschr. wiss. Zool., Bd. in). Leipzig. 
n. V. Belied en, P. J. (1841): Recherches sur la structure de I'oef dans un nouveau genre de Polype (genre Hydractinie). 

I Bull. Acad. so. Bruxelles, vol. 8). Bruxelles. 

12. — (1844): Recherches sur I'embryogenie des Tubulaires et I'histoire naturelles des differents genres de cette famille 

qui habitent la cote d'Ostende. (Nouv. Mem. Acad. Bruxelles, vol. 17). Bruxelles. 

13. Bergli, R. S. (1887): Goplepolyper (H3^droider) fra Kara-Havet. (Dijmphna-Togtets zoologisk-botaniske Udbytte). Kjo- 

benhavn. 

14. Billard, Arm. (1906); Mission des pecheries de la cote occidentale d'Afrique. (Actes Soc. Linn. Bordeaux, Vol. 61). 

Bordeaux. 

15. Boeck, C. (i860): Tubularie fra Belsund paa Spitzbergen — Tubularia regalis. (Vidensk. Selsk. Porhandlinger, Aar 1859). 

Chris tiania. 

16. Bonnevie, K. (1898): Zur Systematik der Hydroiden. (Zeitschr. wiss. Zool. Bd. 63). Leipzig, 

17. — (1898): Neue iiorwegische Hydroiden. (Bergens Mus. Aarbog). Bergen. 

18. — (1899): Hydroida. (Den Nonske Nordhav.s-Expedition 1876— 1878. XXVI). Christi.ania. 

19. Broch, Hj. (1903): Die von dem norwegischcn Fischereidampfer "Michael Sars" in den Jahren 1900— 1902 in deni .Vurd- 

nieer cingesammelten Hydroiden. (Berg. Mus. Aarbog). Bergen. 

20. — ('909): Die Hydroiden der arktischen Meere. (Fauna arctica, Bd. V). Jena, 

21. — (191 1): Fauna droebachiensi.s. L Hydroiden (Nyt Mag. Naturvid. Bd. 49). Kristiania. 

22. — (1914); Hydrozoa benthonica. (Btitrage zur Kenntnis der Meeresfauua Westafrikas). Hamburg. 
23- — (1914): Stylasteridae. (The Danish Ingolf-Kxpedition, Vol. V). Copenhagen. 

24. — (1915): Hydroiduntersuchungen. IV. Beitrage zur Kenntnis der Gonophoren der Tuliulariiden. (l)et kgl. norske 

Vidensk. Selsk. Skr. 1914). Trondhjem. 

25. Clark, H. J. (1865): Mind in nature; or the orgine of life, and the mode of development in animals. New-York. 

26. Khrenberg, C. G. (1834): Beitrage zur physiologischen Kenntniss der Corallenthiere im Allgemeinen uud besonders des 

rothcn Meeres, nebst einem Vcrsuche zur physiologischen Systematik derselben. (.Mihandl. d, K. .\kad. d. Wiss. 
zu Berlin 1832). Berlin. 



HYDROIDA ^ 



27. Ellis, J., and Solander, D. (1786); The natural histon- of many curious and uncommon Zoophytes, collected from 

various parts of the Globe. London. 

28. Fabricius, O. (1780): Fauna Groenlandica. Hauniae et L,ipsiie. 

29. Fenchel, A. (1905): Ueber Tubularia larynx Ellis iT. coronata Abildgaard). Revue Suisse de Zool. Vol. 151. Geneve 

30. Fewkes, J. W I'iSSi): Report on the results of the dredging operations under the supen-ision of Alexander Agassiz 

in the Caribbean Sea. iBuU. Mus Comp. Zool. Harvard Coll. Vol Villi. Cambridge. 

31. Fleming, J. (1S2S1: A History of British animals. Edinburgh. 

32. Forskal, P. (1775I: Descriptiones animalium . . . qu;e in itinere orientali observavit. Haunia;. 

33. Giard, A. (1899): Sur letiologie du Campanularia calyculata Hincks. (C. R. Soc. Biol. Paris. Ser 10, Vol. 5. Paris. 

34. Hadiii, J. (1913): Poredbena hidroidska istrazivanja II. Perigonimus corii sp. n i Perigonimus georginae sp. n. (Rada 

Jugoslav, akad. zuan. i umjetn. knj, 200). Zagreb, 

35. — (1914): Vergleicheude Hydroidenuntersuchuugen II. [E.xtract in the (jerman language of the preceding paperj. (Bull 

d. Travaux de la Classe d. Sci. Math et Natur. fasc i ). Zagreb. 

36. Hartlaub, C. (1905): Die Hydroiden der magalhaensischen Region und chilenischen Kiiste. (Zool. Jahrb. Suppl. 6)- 

Jena. 

37. — (1907): Craspedote Medusen. I Teil, 1. Liefg., Codoniden und Cladoneniiden. (Nord. Plankton. Bd. 6). Kiel und 

Leipzig. 

38. — (1913): Craspedote Medusen. I. Teil. 3 Liefg., Tiaridae, (Nord. Plankton. Bd. b). Kiel und Leipzig. 

39. Hincks, Th. (1868); A History of the British Hydroid Zoophytes. London. 

40. Jaderholm, E (1902): Die Hydroiden der schwedischen zoologischen Polarexpedition 1900. (Bih. Kgl. Vet.-.\kad. Handl 

Bd. 281. Stockholm. 

41. — (1905): Hydroiden aus antarktischen und subantarktischen Meeren. Wissensch. Ergebn. d. schwed. Siidpolar- 

Exped. 1901 — 1903. Bd. 51. Stockholm. 

42. — (190S1: Die Hydroiden des Sibirischeu Eismeeres, gesanmielt von der russischen Polar-Expedition 1900 — 1903. (Mem. 

de I'Acad. Imp. des Sci.). St. Petersbourg. 

43. — (1909): Northern and Arctic Invertebrates in the Collection of the Sv.edish State Mu.seum. IV. Hydroiden. (Kgl. 

Svenska Vet.-Akad. Handl. Bd. 45 . Uppsala & Stockholm. 
44 Johnston, G. (1847): A Historj' of the British Zoophytes. London. 

45. Kramp, P. L. (1911): Report on the Hydroids collected by the Danmark Expedition at North-East Greenland. (Dan- 

mark-Eksped. til Gronlands Nordostkyst 1906 — 190S. Bd. Vl. Kobenhavn. 

46. — (1913I: Hj'droids collected by the "Tjalfe" Expedition to the West Coast of Greenland in 1908 and t9ci9. (Vidensk. 

Meddel. fra Dansk naturh. Foren Bd. 66|. Kobenhavn. 

47. — (1914): Conspectus Faunae Groenlandics. Hydroider. (Meddel. om Gronland XXIII). Kobenhavn. 

48. Kiihn, A (1910): Die Entwickelung der Geschlechtsindividuen der Hydromedusen. Studien zur Ontogenese und Phylo- 

genese der Hydroiden II. (Zool. Jahrb. Vol. 30. Auat. ). Jena. 

49. — (1913): Entwickelungsgeschichte und Verwandtschaftsbeziehungen der Ilydrozoeu. 1. Die Hydroiden. (Ergebn. 

und Fortschr der Zool. Bd. IV). Jena. 

50. Levin sen, G. M. R. (1893^: Meduser, Ctenophorer og Hydroider fra Gronlands Vestkyst. (Vidensk. Meddel. fra den 

naturhist. Foren. i Kjobenhavn for 1892I. Kjobenhavn. 

51. Linne, C. (1758): Systema Naturae. Ed. lo. Holmiae. 

52. Lonian, J. C. C. ,18891: Hydropolypen mit zusammengesetztem Coenosarkrohr. Tijdschr. Nederl. dicrkund. Veren. Ser. 2, 

Vol. 21. Amsterdam. 

53. Loven, S. (1835): Bidrag til Kannedomen af Slagtena Campanularia och Syncoryna. iKgl. svenska Vet -Akad. Handl. 

for Ar 1S35). Stockholm. 

54. V. Lorenz, L. (i8S6i: Polypomedusen von Jan Mayen. Die Oesterr. Polarstation Jan Mayen, Bd. IIIi. Wieu. 

55. Liitken, C. (1850): Nogle Bemserkninger om Medusemes systematiske Inddehng, navnhg med Hensyn tiX Forbes" s History 

of british naked-eyed Mednsce. (Vidensk. Meddel. fra den Naturh. Foren. i Kjobenhavn for 1850;. Kjobenhavn. 

56. V. Marenzeller, E. E. (1878): Die Coelenteraten, Echinodermen und Wiirmer der K. K. Oesterreichisch-Ungarischen 

Nordpol-Expedition. (Denkschr. d. K. Akad. d. Wissensch. Math.-Naturw Classe. Bd. 35X Wien. 

57. Mayer, A. G. (19101: Medusae of the world. Washingtou. 

58. Mereschkowsky, C. (1877): On a new genus of Hydroids from the White Sea, with a short description of other new 

Hydroids. (Ann. and Mag. nat. Hist. Ser. 4, Vol. 20). London. 

o 

The Ingolf-Exptdition. V. 6. ^ 



66 



HYDROIDA 



59. MiiUer, O. F. (1777): Zoologize Daiiicie. Tasc. [. HauiiiaJ. 

60. Kordgaard, O. (1912): Bryozoaires. Due d Orleans. Caiiipagne arctique de 1907). Bruxelles. 

61. Norman, A. M. (1S64): On undescribed British Hydrozoa, Actinozoa, and Polyzoa. (Ann. and Mag. nat. Hist. Ser. 3, 

vol. 13). London. 

62. (1S65':: On Merona, an undescribed genus of British Hydrozoa. CAnn. and Mag. nat. Hist. Ser. 3, vol. 15;. London. 

6^ d'Orbio-nv, A.(l834— 46): Voyage dans I'Amerique nieridionale ... execute dans le cours des annees 1826 — 1.S33. Vol. 5. Paris. 

64. Pallas, P. vS. (1766): Elenchus zoophytoruni. Hagse-Comituni. 

65. Poche, F. (1914); Das System der Coelenterata. (Archiv fiir Naturgesch. Jahrg. So, Abt. A). Berlin. 

66. Quelch, J. J.liSS^); On some Deep-Sea and Shallow-water Hydrozoa. (Ann. and Mag. nat Hist. Ser. 5, Vol. i6\ London. 

67. Ritchie, J. (1907): The Hydroids of the Scottish National Antarctic Expedition. (Transact. Roy. Soc. Edinb. Vol. XLVj. 

E<hnburgh. 

68. Sars, G. O. (1874;: Bidrag til Kundslcaben om Norges Hydroider. (Forhandl. i Vid-Selsk. i Christiania 1S73). Christiania. 

69. Sars, M. (1835): Beskrivelser og lagttagelser over nogle niu5rkelige ellgr nye i Havet ved den Bergenske Kyst leveude 

Dyr af Polypernes, Acalephernes, Radiaternes, Aunelidernes og Molluskernes Classer, nied en kort Oversigt over 
de hidtil af Forfatteren sammesteds fundne Arter og deres Forekonimen. Bergen. 

70. — (1846): Ueber die Fortpflanzungsweise einiger Polypen {Syncoiyna. Podocoryiia, Pcrigoniintis, Cytcsis). {Fauna littoralis 

Norvegise. 1. Hefte). Christiania. 

71. — (1S51): Beretning om en i Sonimeren 1S49 foretagen Zoologisk Reise i Lofoten og F'inmarken. (Nyt Mag. for Na- 

turvid. Bd 6) Christiania. 

72. — (1859,,; Om Annneslaegten Corymorpha, dens Arter, samt de af disse opammede Meduser. (F'orhandl. i Vidensk.- 

Selsk. i Christiania 185S . Christiania. 

73. — (1877): Nye og mindre bekjendte Coelenterater. (Fauna littoralis Norvegiae, Part 3I. Bergen. 

74. Schneider, K. C. (1902): Lehrbuch der vergleichenden Histologic der Tiere. Jena. 

75. Schmidt, O. (1S52): Handatlas der vergleichenden Anatomie. Jena. 

76. Stechow, E. (1912): Hydroiden der Miinchener Zoologischen Staatssammlung. (Zool. Jahrb. Bd. 32, System.). Jena. 

77. — (1913): Hj'droidpolypen der japanischen Ostkiiste. IL Teil. (Abh. math.-phys. Kla.sse der K. Bayer. Akad. Wiss. 

in. Suppl.-Bd.). Miinchen. 

78. Steenstrup, J. 1842): Oni Foqilantning og Udvikling gennem vexlende Generationsriekker, en saeregen Form for Op- 

fostringen i de lavere Dyreklasser. Kjiibenhavn. 

79. — (1S54): En ny og tropisk Art af Smaagoplernes Amtnesltegt: Corymorpha Sars (Corymorpha Januarii ,Stp. 1. — (Vi- 

densk. Meddel. naturh. Forening i Kobenhavn for 1854}. Kobenhavn. 

80. Swenander, G. (1904I: Uber die Athecaten Hydroiden des Drontheimfjordes. (Det Kgl. norske Vidensk. Selsk. Skrifter 

1903). Trondhjem. 
Si. Set-mu ndsson , B. 11S99): Aiiliscus pulchi-r, en ny Goplepoh'p med frie Meduser. Zool. Meddel. fra Island. V. (Vidensk. 
Meddel. naturhist. Foren. i Kobenhavn 1899). Kobenhavn. 

82. — (1902): Bidrag til Kundskaben om de islandske Hvdroider. (Vidensk. Meddel. naturhist. Foren. i Kobenhavn 19021. 

Kobenhavn. 

83. — {1911): Bidrag til Kundskaben om de islandske Hydroider. II. (Vidensk. Meddel. naturhist. Foren. i Kohenhavn 

191 1). Kobenhavn. 
,84. Torrey, II. B. (1907): Biological Studies on Corymorpha. 2. The Development of C. pahna from the egg. (L'niv. Cali- 
fornia Publ. Zool., vol. 3). Berkeley. 

85. VanlKiff en, E. (1909): Die Hydroiden der deutschen Siidpolar-Expcdition igoi — 1903. (Deutsche Siidpolar-Iixjieditioii 

1901- 1903, Bd. XI, Zool. Bd. III). Bcrhn. 

86. Wagner, J. (1890): Recherches sur I'organisation de Monobrachiuni parasiticum Merej. (Arch. Biol, Vol. lol 

87. Weismann, A. 11SS2): Uber eigenthiimliclie Organe bei Eudendrium racemosura Cav. (Mittheil. Zool. Station zu Nea- 

pil. Bd. 3). Leipzig. 

88. Wiuther, G. (1880): Fortegnelse over de i Daumark og dels nordlige Bilaiule fundne hydroide Zoophyter. (Naturhist. 

Tidsskr, vol. 121. Kobenhavn. 

89. Wright, T. S. (1857): Observations on british Zoophytes. (Edinb. new philos. Journ. New Ser. Vol. 6. Edinburgh. 

90. — (1859): Observations on british Zoophytes. (Edinb. new philos. Journ. New Ser. Vol. 10). F:dinburgli. 



Plate I. 



-1- 



Plate I. 

Fig. I. Nematocyst from the tentacle of Moi/ocorync gigantea. Delafields haematoxyline — Iron 
annnonium sulfate, ''-^"/i. 

— 2. Nematocyst from the tentacle of Coryuc Lovcni. Boehmers haematoxyline — Iron ammoninm 

sulfate. '75%. 

— 3. Nematocysts from the tentacle of Myriotlicla phrygia, a: of the general, ovoid type, b: of 

the rarer, narrow type. Delafields haematoxyline — Iron ammonium sulfate. '75°/,. 

— 4. Nematocyst from the tentacle of Tubularia indivisa. Delafields haematoxyline — van Giesson. 

'750/^. 

— 5. Neinatocjst from the tentacle of Clava iiiuUicornis. Delafields haematoxyline — Iron ammo- 

nium sulfate. '75fyj. 

— 6. Nematocyst from the tentacle of Bougainvillia ramosa. Delafields haematoxyline — Iron 

ammonium sulfate. '75°/^. 

— 7. Nematocysts from Eiidcndrium Wright i\ a: small type from the tentacles, b: larger type 

from the belt of stinging cells at the base of the polyp body. Delafields haematoxyline — Iron 
ammoniiim sulfate. '75"/^. 

— 8. Myriothela phrygia; mutilated specimen from the "Ingolf" st. 125. ^/j. 

— 9. Hydractinia cchinata ; spines from the Greenland specimen. ^/,. 

— 10. — — specimen from Greenland with extraordinarily large spines, ^/j. 

— II. Hydractinia carica; spines from the type specimen, '^j^. 

— 12. Hydractinia Sarsii; spines from a specimen from Godthaab harbour, wrongly labelled 

^'■Podocoryne carnea". ^/j. 



The Ingolj' Expedition, V. 6. 



Broch: Hydroida. Plate I. 




/>. 



/ 



^f 



^A 



-~\r\ 



\ 





3a 





n 





10 



1 



11 



\ 




V 



12 



Hj Broch del. et phot. 



Ljusir. A. B. Lagrelius & Wcslphal. Stockholm 



Plate II. 



Plate XL 

Fig. 13. Corync I.oveni; specimen from Bjarkoy, Northern Norway, ^"/i. 

— 14. Coryviorpha groenlatidica ; one of A 11 mans type specimens of Monocaulus groenlandica show- 

ing the young blastostyles as mere sacs without any trace of the single gonophores. 3°/,. 

— 15. Corymorpha groenlandica from the Davis street, wrongly labelled ^'■Ai/ialthcea islandica". 

Nat. size. 

— 16. Tiibularia pulchcr. Gonophore of one of the type specimens of ^'■Aiiliscus piilchcr" . ^°/i. 

— 17. Mer 0)1(1 cornucopia; on Card mm sp. from the Faroe-islands. 3o/j. 



The Ingolf Expedition, V, 6. 



,./? 



r\A 



\A -? 



yn 



M 



jm 



'? 



Broch: Hydroida. Plate II. 




'D 



rf 



If) 



\ 



u 



13 




'/ 






\ 



16 



n 



Hj Broch del. el phot. 



L)U5ir. A. B. Lagrclius & Wcstphal, Stockholm 



THE INGOLF-EXPEDITION 



1895 — 1896. 



THE LOCALITIES, DEPTHS, AND BOTTOMTEMPERATURES OF THE STATIONS 



Station 

Nr. 


Lat. N. 


Long. W. 


Depth 

in 
Danish 
fathoms 


Bottom- 
teinp. 


Station 

Nr. 


Lat. N. 


Long. W. 


Depth 

in 
Danish 
fathoms 


Bottom- 
temp. 


Station 

Nr. 


Lat. N. 


Long.W. 


Depth 

ill 
Danish 
fathoms 


Bottom- 
terap. 


I 


62° 30' 


8°21' 


132 


7°2 


24 


63° 06' 


56° 00' 


1199 


2°4 


45 


61° 32 


9° 43' 


643 


I°i7 


2 


63° 04' 


9° 22' 


262 


5°3 


25 


63° 30' 


54° 25' 


582 


3°3 


46 


61° 32' 


11° 36' 


720 


J 4u 


3 


63° 35' 


10° 24' 


272 


o°5 




63° 51' 


53° 03' 


.36 




47 


61° 32' 


13° 40' 


950 


3°23 


4 


64° 07' 


11° 12' 


237 


2°5 


26 


63° 57' 


52° 41' 


34 


o°6 


48 


61° 32' 


15° II' 


1 150 


3°i7 


5 


64° 40' 


12° 09' 


155 






64° 37' 


54° 24' 


109 




49 


62° 07' 


15° OT- 


1120 


2°9I 


6 


63° 43' 


14° 34' 


90 


7°o 


27 


64° 54' 


55° 10' 


393 


3°8 


50 


62° 43' 


IS" 07' 


1020 


3°i3 


7 


63' 13' 


15° 41' 


600 


4°5 


28 


65° 14' 


55° 42' 


420 


3°5 


51 


64° 15' 


14° 22' 


68 


7°32 


8 


63° 56' 


24° 40' 


136 


6°o 


29 


65° 34' 


54° 31' 


68 


0°2 


52 


63° 57' 


13° 32' 


420 


7°87 


9 


64° 18' 


27° 00' 


295 


s°s 


30 


66° 50' 


54° 28' 


22 


i°05 


53 


63° 15' 


15° 07' 


795 


3°o8 


lO 


64° 24' 


28° 50' 


788 


3°5 


31 


66° 35' 


55° 54' 


88 


i°6 


54 


63° 08' 


15° 40' 


691 


3°9 


II 


64° 34' 


31° 12' 


1300 


i°6 


32 


66° 35' 


56° 38' 


3>8 


3°9 


55 


63° 33' 


15° 02' 


316 


s'g 


12 


64° 38' 


32° 37' 


1040 


o°3 


33 


67° 57' 


55° 30' 


35 


o°8 


56 


64° 00' 


15° 09' 


68 


7°57 


13 


64° 47' 


34° 33' 


622 


3°o 


34 


65° 17' 


54° 17' 


55 




57 


63° 37' 


13° 02' 


350 


3°4 


H 


64° 45' 


35° 05' 


176 


4°4 


35 


65° 16' 


55° 05' 


362 


3°6 


58 


64° 25' 


12° 09' 


211 


o°S 


15 


66° i8' 


25° 59' 


330 


-o°75 


36 


61" 50' 


56° 21' 


1435 


i°5 


59 


65° 00' 


n°i6' 


310 


O"! 


i6 


65° 43' 


26° 58' 


250 


6°i 


37 


60° 17' 


54° 05' 


1715 


i°4 


60 


65° 09' 


12° 27' 


124 


o°9 


17 


62° 49' 


26° 55' 


745 


3°4 


38 


59° T 2- 


51° 05' 


1870 


i°3 


61 


65° 03' 


13° 06' 


55 


o°4 


i8 


61° 44' 


30° 29' 


1135 


3°o 


39 


62° 00' 


22° 38- 


865 


209 


62 


63° 18' 


19° 12' 


72 


7092 


19 


60° 29' 


34° 14' 


1566 


2°4 


40 


62° go' 


21° 36' 


845 


-.0., 




63 


62° 40' 


19° 05' 


800 


4°o 


20 


58° 20' 


40° 48' 


1695 


i°5 


4t 


61° 39' 


17° 10 


1245 


2°0 


64 


62° o6- 


19° 00' 


1041 


3=1 


21 


58° 01' 


44° 45' 


1330 


2°4 


42 


6i°4i' 


10° 17' 


625 


o°4 ' 


65 


61° 33' 


19° 00' 


1089 


3°o 


22 


58° lO' 


48° 25' 


1845 


i°4 


43 


61° 42' 


10° 11' 


645 


o°o5 


66 


61° 33' 


20° 43' 


1128 1 


3°3 


23 


60° 43' 


56° 00' 


Ouly the 

Plankton-Net 

iiatd 




44 


61° 42' 


9° 36' 


545 


4°8 


" 


61° 30' 


22° 30' 

i 


975 


300 



station 

Nr. 


Lat. N. 


Long.W. 


Depth 

in 
Danish 
fathoms 


Bottom- 
temp. 


Station 

Nr. 


Lat. N. 


Long. W. 


Depth 

in 
Danish 
fathoms 


Bottom- 
temp. 


Station 

Nr. 


Lat. N. 


Long.W. 


Depth 

in 
Danish 
fathoms 


Bottom- 
temp. 


68 


62° 06' 


22° 30' 


843 


3°4 


92 


64° 44' 


32° 52' 


976 


i°4 


118 


68° 27' 


8° 20' 


1060 


-i°o 


69 


62° 40' 


22° 17' 


589 


3°9 


93 


64° 24' 


35° 14' 


767 


i°46 


119 


67° 53' 


10° 19' 


lOIO 


-i°q 


70 


63° 09- 


22° 05' 


134 


7"o 


94 


64° 56' 


36° 19' 


204 


4° I 


120 


67° 29' 


11° 32' 


S85 


-i°o 


71 


63° 46' 


22° 03' 


46 






65° 31' 


30° 45' 


213 




121 


66° 59' 


13° 11' 


529 


-o°7 


72 


63° 12' 


23° 04' 


197 


6°7 


95 


65° 14' 


30° 39' 


752 


2°I 


122 


66° 42' 


14° 44' 


115 


i°8 


73 


62° 58' 


23° 28' 


486 


5°5 


96 


65° 24' 


29° 00' 


735 


1°2 


123 


66° 52' 


15° 40' 


145 


2°0 


74 


62° 17' 


24° 36' 


69s 


4°2 


97 


65° 28' 


27° 39' 


450 . 


5°5 


124 


67° 40' 


15° 40' 


495 


-o°6 




61=57' 


25° 35' 


761 




98 


65° 38' 


26° 27' 


138 


5°9 


125 


68° 08' 


16° 02' 


729 


— o°8 




61° 28' 


25° 06' 


829 




99 


66° 13' 


25° 53' 


187 


6°i 


126 


67° 19' 


15° 52' 


293 


-o°5 


75 


61° 28' 


26° 25' 


780 


4°3 


100 


66° 23' 


14° 02' 


59 


o°4 


127 


66° 33' 


20° 05' 


44 


5°6 


76 


60^^ 50' 


26° 50' 


806 


4° I 


lOI 


66° 23' 


12° 05' 


537 


-o°7 


128 


66° 50' 


20° 02' 


194 


o°6 


77 


60° 10' 


26'' 59' 


951 


3°6 


102 


66° 23' 


10° 26' 


750 


-o°9 


129 


66° 35' 


23° 47' 


117 


6°5 


78 


60° 3/ 


27° 52' 


799 


4°5 


103 


66° 23' 


8° 52' 


579 


-o°6 


130 


63° oo' 


20° 40' 


338 


6°55 


79 


60° 52' 


28° 58' 


653 


4°4 


104 


66° 23' 


7° 25' 


957 


— i°i 


131 


63° CO- 


19° 09' 


698 


4°7 


So 


61° 02' 


29° 32' 


935 


4°o 


105 


65° 34' 


7° 31' 


762 


-o°8 


132 


63° 00' 


17° 04' 


747 


4°6 


81 


61° 44' 


27° 00' 


485 


6° I 


106 


65° 34' 


8° 54' 


447 


-o°6 


133 


63° 14' 


11° 24' 


230 


2°2 


82 


6i°.S5' 


27° 28' 


824 


4° I 




65° 29' 


8° 40' 


466 




134 


62° 34' 


10° 26' 


299 


4° I 


83 


62° 25' 


28° 30' 


912 


3°5 


107 


65° 33' 


10° 28' 


492 


-o°3 


135 


62° 48' 


9° 48' 


270 


o°4 




62° 36' 


26° 01' 


472 




108 


65° 30' 


12° 00' 


97 


i°i 


136 


63° 01' 


9°ii' 


256 


4°8 




62° 36' 


25° 30' 


401 




109 


65° 29' 


13° 25' 


38 


^"5 


137 


63° 14' 


8° 31' 


297 


-o°6 


84 


62° 58' 


25° 24' 


633 


4°8 


no 


66° 44' 


11° 33' 


781 


— o°8 


138 


63° 26' 


7° 56' 


471 


-o°6 


85 


63° 21' 


25° 21' 


170 




III 


67° 14' 


8° 48' 


860 


-o°9 


139 


63'' 36' 


7° 30' 


702 


-o°6 


86 


65° 03'6 


23° 47 '6 


76 




112 


67° 57' 


6° 44' 


1267 


— i°i 


140 


63° 29' 


6° 57' 


780 


--o°9 


87 


65° 02'., 


23° 56'. 


no 




113 


69° 31' 


7° 06' 


1309 


-i°o 


141 


63° 22' 


6° 58' 


679 


-o°6 


88 


64° S8' 


24° 25' 


76 


6°9 


114 


70° 36' 


7° 29' 


773 


-i°o 


142 


63° 07' 


7° 05' 


587 


-o°6 


89 


64° 45' 


27° 20' 


310 


8=4 


115 


70° 50' 


8° 29' 


86 


0°I 


143 


62° 58' 


7° 09' 


388 


-o°4 


90 


64° 45' 


29° 06' 


568 


4°4 


116 


70° 05' 


8° 26' 


371 


-o°4 


144 


62° 49' 


7° 12' 


276 


i°6 


91 


64° 44' 


31° 00' 


1236 


3°' 


117 


69° 13' 


8° 23' 


1003 


— i°o 













-»S*<3>-. 




1 



,v 



v^ 



= I E I 8 |i 



H-;.^ 



p 



THE DANISH INGOLF-EXPEDITION. 



VOLUME V. 



7. 



HYDROIDA 

(PART II.) 



BY 



HJALMAR BROCH. 



o 



WITH I PLATE AND 95 FIGURES IN TEXT. 



->-^'t:?<f<- 




COPENHAGEN. 

PRINTED BY BIANCO LUNO. 
191 8. 



\ I' 



CONTE 



Page 
I. Comparative anatomy of the iiourisliing individuals, and 

svsteniatic division of the thecaphore hydroids i 

II. Thecaphore Hydroids of the Northern Atlantic 6 

Family series Heb,lUita 6 

Family Lafaidu- 6 

LafcTa (Lamouroux) 7 

Laftea diiinosa (Fleming) 7 

— gracillima (Alder) 9 

— fiutkosa M. S a rs 12 

Toichopoma Levinsen 15 

To?chopoma obliquum (Hincks I 15 

Grammaria ( S t i m p s o n ) l5 

Grammaiia serpens (Hassallj 16 

— eonfcrta ( A 11 man ) 17 

— abietina ( M. S a rs) 18 

— immersa Nutting 22 

Lictorella ( A 1 1 m a n ) 22 

Lictorella piiinata ( G. O. Sa rs) 22 

Zygophylax Q u e 1 c h 24 

Zygophylax biannata B i 1 1 a r d 24 

Family Campaunliiudie 25 

Subfamily Cuspidellince 26 

Stegopoma Levinsen ' 26 

Stegoponm plicatHe ( M. S a rs ) . ; 25 

Ciispidella Hincks 29 

Cuspidella hiiiiii/is Hincks... 29 

Lafoeina 51. S a rs 29 

Lafoeina maxima Levinsen 30 

Campantilind van B e n e d e n 30 

Campaniibna turrita Hincks 31 

Subfamily Calycellni<i 32 

Calycella (Hincks) 32 

Calycella syringa (Linne) 32 

Tetrapoma Levinsen 34 

Tctrapama qitadridentatum (Hincks) 34 

Family series Haleciina 35 

Family Haleciida: : -. 35 

Halecium Oken 35 

Halecutm halecinum (Linne) 36 

— Beaiiii Johnston 38 

— scutum Clark 39 

— curvicaule v. Lo r e n z 41 



NTS 

Pace 

Halecium muncatum (Ellis and SolanderV... 43 

— labrostim Alder 45 

— tenellum Hincks 46 

— minutum Broch 50 

Family Plumularitdu- 51 

KircheHpaueria ( J I ck e 1 i ) 52 

Kirchenpaueria pinnata (Linne) 53 

Plumularia (Lamarck) 55 

Phimularia setacea (Linne 55 

— Catliarina Johnston 56 

Polyplumaria G. O. S a rs 58 

Polyplumaria frutescens (Ellis and Solander) . 59 

— flabellata G. O. Sars 59 

— J>rofunda (Nutting) 60 

''"iNemcrlesia Lamouroux 62 

^^emeftesia antejinina (Linne) 64 

— ramosa Lamouroux 66 

Polynemertesia nov. gen. 69 

Polynemcrtesia graalliina (G. O. Sars) 70 

Family Aglaophcniida 72 

Halicornaria (Busk) 72 

Halicornaria campatiulata (Ritchie) 72 

Nematocnrpus nov. gen 74- 

Nematocarpiis ramuliferus ( .^ 1 1 m a n ) 74 

Aglmphenopsis ( Fe vv kes ) 77 

Aglaopheuopsis eoruuta ( V e r r i 1 1 ) 77 

— (?) pharetra nov. sp So 

Cladocarpus A 1 1 m a n 82 

Cladocarpus integer 1, G. O. Sars 1 82 

— formosus A 11 m a n 85 

— Diana nov. sp 87 

— bictispis ( G. O. S a rs ) 89 

Thecocarpus Nutting 9' 

Thecocarpus myriopkyllum ( Lmne) 92 

Aglaopht-nui (Lamouroux) 93 

Aglaophenia tubulifera Hincks : 93 

Family series Sertulariina 94- 

Family Sertulanida 94 

Scrtularella Gray 9^ 

Sertidarella tama risen ( Li n u e I 96 

— . tricuspidata ( .-\ 1 d e r ) 98 

— amphorifera .-M 1 m a n lOO 



Page 
Serhitaria polygon/as (Linne) loi 

— Gayi (Lamouroux) 102 

— teitella (Alder) 104 

— fusiformis Hin cks 105 

rugosa (Linne) 106 

Diphasia Agassiz 107 

Diphasia fallax (Johnston | loS 

— IVandeli Levinsen Ill 

• — rosacea (Linne) 112 

— attenuata Hin cks II3 

— alata Hi neks 114 

Dynamcna (Lamouroux) I14 

Dynamena piimila (Linne) I15 

Abietitiaria ( Kir chenpauer) 116 

Atietinaria nbiettna ( Linne) 117 

— yf//«^Aj ( Ellis et Solan der) 119 

— Q)fusca (Johnston) 1 20 

Sertular/a (Linne) 122 

Sertttlan'a cttpressiua Linne 124 

— Um-ra G. O. Sars 127 

— Fabiicii Levinsen 130 

— (?) tuhiiliyoinns (M ark tan ner-Tu rneret- 

scher) 132 

— tnirabilis ( Verrill) 133 

Hydrallmania Hi neks 134 

Hydrallinania fatcala (Linne) 135 

Thujaria (Fleming) 13S 

Thujaria thtija (Linne) 1 39 

— sp. aff. hippuris Alhn an , 141 

— laxa All man 142 

— alternitheca Levinsen 143 

— variabilis nov. nom 145 

— /oKf/i/'/w ( Ellis et Solander) 146 

— carica Levinsen 148 

— sp. af f . distans Fraser 14S 



Page 

Family series Proboscoida 149 

Family Campanulariida 149 

Campamtlaria (Lamarck) 153 

Campanularia vohibilis (Linne) 153 

— verticillttta (Lionel 155 

— groenlandica Levinsen 157 

— speciosa Clark 158 

— integra Mac Gillivra}- 159 

— Hincksi Alder 162 

— JoJiiistoiii Alder 163 

Laomedea Lamouroux... 164 

Laomedea flexriosa Alder 165 

— geniculata (Linne) 166 

— longissima (Pallas) 167 

— hyalina (Hi neks) 169 

— gracilis M. .Sars 170 

Bonneviella Bro eh 172 

Bonneviella grandis (All man) 173 

III. Addenda to the Atheeate Hydroida 174 

Coryniorpha nutans M. .Sars 1 7.J 

— groenlandica ( A 1 1 m a n ) 174 

Family Branchiocerianthida 174 

Bratichiocerianthus Mark 174 

Bratichiocerianthus reniformis nov. sp 176 

IV. Zoogeographical obser\ations on the Hydroid Fauna 

of the North Atlantic 178 

V. List of the genera treated, and type-species 195 

Literature 197 

VI. Index 201 

Errata 206 



I. Comparative anatomy of the nourishing individuals, and 
systematic division of the thecaphore hydroids. 



As with the athecate hydroids, so also in the case of the thecaphores, the comparative anatomy 
of the nourishing individuals affords us a certain working basis in systematical respects. With regard 
to this group, however, the investigations are still somewhat incomplete, as will be seen from the 
following. 

The ectoderm of thecaphore hydroids is apparently very uniform in point of development, 
and the nematocysts, which in the athecates furnished good material for study, seem in the theca- 
phores to vary but slightly, and should on the whole be referred to the same type as in Athecata 
filifera. This point is of some considerable interest as further confirmation of the old theory as to a 
closer relationship between the thecaphores and the mentioned group than between the thecaphores 
and Athecata capitata. Even among the Grammaria, where the nematocysts, in one species at any 
rate, are dimorphously developed, we can find no resemblance to the capsule form in Athecata capitata. 
The arrangement of the stinging cells also is very nuiforni in the thecaphores. As a general rule, 
we may say that the nematocysts in the thecaphores appear in marked transverse zones about the 
tentacles; the only exception I have found here is that of the gigantic Bonneviella polyps, where the 
zonate arrangement has become effaced. 

A somewhat different organisation of the ectoderm is encountered in one or two families. The 
grown polyps of Syntheciida^ and Sertii/ariiJcr have developed adhesive lamella, an exterior ectodermal 
lamella covering the inner side of the hydrotheca for a greater or lesser extent when the polyp has 
withdrawn into the same. It is this ectodermal lamella which Nutting (1904 p. 10) considers as one 
or more "protractors", evidently from more or less accidental breaks in the lamella, this being, in the 
living polyps, continuous. Nutting even goes so far as to base part of his system upon the number 
of "protractors", and is here followed by Broch (1905, 1909). These protractors, however, form, as 
pointed out by Kiihn (1913 p. 66) an unbroken sheath or covering on the inner side of the hydro- 
theca, attached at its basal margin to the body of the polyp, and at the distal to the opercular appa- 
ratus. A similar arrangement is also found in Aglaopheiiiidcr; here likewise we encounter lamellous 
extensions of the ectoderm, attaching the polyp to the inner ribs of the hydrotheca. 

We see then, that the ectoderm itself gives us very little to go upon in a systematic classifi- 
cation. On the other hand, its derivates, i. e. the periderm, will in the thecaphores be found of great 
importance in this respect. The thecaphores are, as we know, characterised by their stiff, almost 

Tlie logolf-Expcdilion. V. 7. I 



HYDROIDA II 



chitinous sheath, which is extended to form the hydrotheca. Incipient hydrotheca formation is fonnd 
once or twice among the athecates, as for instance in Pcn'goiiinins, where a folding pseudo-hydrotheca 
surronnds tlie pol>-p below the tentacle whorl. Less attention has perhaps been paid to similar for- 
mations in a species snch as Eudendrmm vagina tuvi All man, ihongh even here we seem to find 
trace of an incipient hydrotheca. In the thecaphores, however, the hydrotheca has developed into a 
permanent component of the colony, and up to now, the systematic arrangement of the thecaphores 
as a whole has been based mainly upon the hydrotheca and its features. In some few families snch 
as HaleciidcF, Phcmtdariida: and SiHcitlariida; the hydrotheca is so small that the polyp cannot as a 
rule be withdrawn entirely into it; often, indeed, the hydrotheca seems merely to furnish a support 
for the basal part of the polyp. In view of the other structural conditions of the polyp, however, 
this must not be regarded as a purely primary feature, but should apparently in most cases be con- 
sidered secondary, as is shown more particulaiiy by the two first-named families. Despite the fact 
that the hydrotheca in La/oridtr, for instance, is far more highly developed, we must nevertheless, from 
the structure of the polyp, consider the last-mentioned family as representing a more primitive stage 
in the process of development. 

A point of more importance is whether the ground plan of the hydrotheca is radial or bilateral. 
This again is generally connected with the presence or absence of stalk. The stalked, and thus 
free hydrotheca, will as a rule be constructed on a radial base type, as seen in Lafocidw^ Campami- 
linidce.^ and CampaTmlariidcB. The more or less marked curvings of the hydrotheca, not infrequently 
found particularly in LafoeidcF^ do not suffice to efface the radial base type, and even in Lafoeida 
and Campanitlinid(f^ where the hydrotheca is sessile or even partly fused with the stolons, the radial 
type is distinctly perceptible. In Silicnlariidcr, on the other hand, the hydrotheca is assymmetrical or 
bilateral, the cause of which peculiarity it is by no means easy to comprehend, since the hydrotheca 
is quite freely set on its stalk, which is as a rule of considerable length. This family is, however, 
altogether but imperfectly known up to now. The sessile hydrotheca has a greater tendency to devel- 
op bilaterally. In the Plumulariida^ this tendency is not yet quite pronounced; we find, however, 
that the diaphragm in most of the species takes up an oblique position relatively to the longitudinal 
axis of the hydrotheca. In Aglaopheniidcc^ the development has proceeded considerably farther, the 
diaphragm here being either markedly oblique or else generally falling into two obliquely set portions, 
whereby the symmetry is arranged about a sagittal plane. This sagittal plane is often also found to 
be the plane of symmetry for the hydrotheca as a whole, the arrangement of the teeth at the opening 
being symmetrical according to the mentioned plane, while at the same time, a more or less marked 
lateral compression is observed in the hydrotheca. A similar bilateral development of the hydrotheca 
is encountered in Syntheciida: and Sertulariidce, where the diaphragm is as a rule also oblique, although 
rarely, if ever, falling so distinctly into two halves as in several of the Aglaopheniida. In Sertula- 
riidm also, the distal parts of the hydrotheca show a distinct bilateral construction according to the same 
sagittal plane as in the diaphragm. 

A secondary formation in the hydrotheca, the closing apparatus, is likewise of considerable 
importance in systematic respects. In one genus of the Lafo'eidcB, Toichopoiiia, we find a very primitive 
type of closing apparatus; the lid here is simply formed by the one side of the distal end of the 



HYDROIDA II 



hydrotheca, which is somewhat thinner than the wall of the hydrotheca generally, and can be brought 
in over the apertnre of the hydrotheca, so as to close it. Within the family of Campanulinidxc^ several 
types of lid have been developed, some consisting of the distal part of the hydrotheca (subfamily 
CnspidellincE) others formed by the primary roof of the hydrotheca (subfamily Calycellincr). The 
closing apparatus in the first case consists of folding, membranous parts, roof-shaped or conical, covering 
the opening of the hydrotheca. In the latter case they form a conical roof, consisting partly of folding 
membrane, partly of triangular plates; in this group, the closing apparatus is always sharply marked 
off from the hydrotheca, whereas in the CusptdellincE, it passes gradually over into the same. In Ser- 
tulariidcv also, we find several forms of closing apparatus either consisting of some few separate tri- 
angular plates, and thus exhibiting the same type as certain Campauiilinidcr^ or reduced to two — 
sometimes even a single plate — but they always appear to be formed from the original roof of the 
li}-drotheca, in contrast to Toicliopoma and CiispidellincE. 

These features have been the subject of general attention in systematic respects; less considera- 
tion, on the other hand, has been devoted to the different structural conditions in the polyps them- 
selves, as arising from varying conditions in the endoderm. 

In Lafoeidcc and Caiiipaniilinidcr, the endoderm is, as a whole, but little differentiated; here 
also, however, we find an oral part above the tentacle whorl, where the indifferent cells with small 
nuclei are decidedh- in the majority, and the structure of the polyps here strikingly resembles that of 
the Bongainvilliidcr. In Haleciidcr^ on the other hand, ve find practically throughout, a marked distinc- 
tion below the tentacle whorl between a fore-stomach and the actually digesting, basal part, the sto- 
mach itself. While the digestive cells in the former are decidedly in the rainoritv, it is they alone 
which form the endoderm of the stomach. The same differentiation into two stomach sections is still 
more pronounced in Fhiiiuilariidcr, and in the 2Dol\-ps of both families we must notice a ring-shaped, 
external constriction of the polyp, where the boundary between the two endodermal zones must be 
taken to lie. The same division of the endoderm of the polyp into two regions is likewise found in Agla- 
opheniida^ but it is not always so easily distinguishable here on mere external observation of the 
polyp, being in particular frequently obscured by the ectodermal extensions previously referred to, by 
which the hydranth is attached to the inner ribs of the hydrotheca. 

Even more pronounced is the differentiation of the endoderm in most of the Synthcciidce and 
Scrtiilariidic. Here, the polyps are as a nUe furnished with a single (ventral) blind sack placed 
abcaulinall)' to the colony. The endoderm of the stomach parts, otherwise formed by a high cylindric 
epithelium, forms in the blind sack only a low epithelium, which does not appear to contain digestive 
elements. This seems to suggest that Kiihn's supposition (1913 p. 68) is correct, and that the abcaul- 
ine blind sack in these families serves for storage of nutritive matter to be digested subsequently, when 
the polyp is again in a resting position. The abcauline blind sack must be said to be characteristic of 
the two families, even though in primitive forms such as for instance Thyroscyphus and Dyna7He?ia, 
only an indication of it may be found. 

Finally, there is }-et another type of polyp found in Campanulariidm and Siliculariidce. While 

all the remaining families of thecaphores are characterised by a conical peristome, this is, in the 

two mentioned families, clubshaped, situate with a narrow base above the tentacle whorl on the broad 

I* 



HYDROIDA II 



body of the polyp. In external habitns, the polyps of these families thus markedly resemble those of 
Eudendriidcp, and the similarity in point of internal structnre is equally remarkable. The endoderm 
of the peristome, or the proboscis, is quite predominantly composed of indifferent cells, while the 
gastral part has a fairly homogeueous endodermal covering of digestive cells. Owing to the devia- 
tion of the polyps in external habitus, I have in a former work, (1909 p. 133) marked off these two 
families as a separate sub-order, Proboscoidea. Considering the mentioned features of organisation, 
however, in the light of what has been stated above, it will hardly be correct to retain this sub- 
order; but it forms a special family series, ranking with the others, where the thecaphores as a whole 
must be said to fall, as will be further referred to in the following. 

A much disputed group is formed by the genus Bonncvirlla, which I formerly (1909 a) noted 
off as a separate family. Kiihn (1913 p. 252) inclines to the view that the genus must be referred 
to La/oeidm, whereas Nutting, in his latest work (191 5 p. 94) retains the family of Boniu-viellida. 
Such description as has been given of the anatomical conditions in this species is as a matter of fact 
not sufficient fully to elucidate the relationship of the group, and Nutting's explanation, in which 
he considers that my previous observations may be confirmed, still lacks the essential point required; 
to wit, the development of the so-called "veloid". A comparison with the remaining genera has led 
me rather to incline towards Kiihn' s theory, that the formation in question can hardly be regarded 
as altogether ectodermal, the inner layer being probably rather an extreme development of the indiffe- 
rent cells of the endoderm. If this supposition prove correct — a point which can only be determined 
by study of the development of the polyps — the position of the genus will nevertheless still be 
doubtful; most of the facts would then seem to lead towards their inclusion as a high form of devel- 
opment of CampanulariidcB] we may, however, also with good reason suppose the origin to be in 
Lafoeidce. Having no suitable material for further study of these questions available, I do not pur- 
pose here to enter upon further theoretical discussion as to the systematic position of the genus. I 
would merely point out once more, that the interpretation of the peristome as an ectodermal gullet 
is doubtful in the highest degree. 

On summing up the above anatomical data, we find that the thecaphore hydroids fall into 
four main groups or series of families, which are of great interest from a phylogenetic point of view. 
The most primitive family .series is that of Hfbflh'na, with its conical proboscis and with homogeneous 
gastral endoderm. This group, which embraces the families La/oeida-, and Cauipamdiuida:^ exhibits a 
marked affinity with the athecatc family of DoiigainviUiida\ and probably originated from the same. 

From HebelUna again, two new family series are derived, viz: on the one hand that of Hale- 
cttna, with the families Haleciidcr^ Pluviulanlda; and Aglaopheniidcr^ and on the other, the series Ser- 
tulariina, with the families of Syntheciidm and Ser hilar iida;. Halecima is characterised by its bipartite 
gastral portion, which is divided into a fore-stomach (probably non-digesting) and a digestive basal 
part. This division is, especially in certain primitive llalccmm species, still but slightly pronounced, 
thus giving the transition from Hcbellina. In Serhdariidar, on the other hand, the basal, one-sided blind 
sack is developed as a storage chamber; the transition from Hcbellina is here represented by forms such 
as Thyroscyphus, where the partition of the gastral parts into the divisions named is still barely indicated. 

An exceptional position is thai of the Proboscoida series, with club-shaped proboscis. The 



HYDROIDA II 



group may be supposed to origiuate from Ilfhrl!iua\ there is, however, much which would seem to 
suggest closer relatiouship with Eudcndriida-. I have in a previous work (1909 p. 132) drawn atten- 
tion to several features pointing in this direction; Kiilin, (1913 p. 246) endeavours to disprove the 
close resemblance, while on the other hand Nutting, (1915 p. 20) notes further similarities, and, like 
Stechow, (1913 p. 22) comes to the conclusion that a close relationship between Proboscoida and 
Etidendriida; is not to be denied. I would here merely mention one point, which Kiihn regards as of 
great importance, but which Nutting has not subjected to closer consideration. Kiihn finds that there 
is a difference of principle in the gonosomes. In this connection, several of the gonangia of the 
Catiipa)iulariid(r will be found of considerable interest. In the athecates, we repeatedly find that single 
gonophores, as in Buugaijivillea, Hydractiiiia^ and Endetidriu7)i^ collect on the stalks of some few 
hydranths; in several species moreover, we find a reduction of the terminal polyp, so that the whole 
of the gonophoriferous complex is here transformed into a blastostyle. As a matter of fact, we have 
in such cases to deal with gonangia aggregates, differing only in gonotheca formation from the gono- 
some in sjaecies such as for instance Laoiiirdca flcxuosa. The development of the gonangia here 
shows us a reduced terminal pol\'p, which has now formed an "Endplatte", on the stalks of which 
gonophores appear. If at the same time we imagine that the gonophores do not penetrate the peri- 
sarc, but that the latter expands instead into a protecting sheath, we lia\e then the gonotheca in 
its typical form for Cai»panulariid(r. It may also be imagined as arising by formation of gonophores 
on the basal parts of the hydranth, within the Indrothtca, when, on the one hand, the hydranth will 
thereby be reduced to an "Endplatte", while on the other hand, hypertrophy of the hydrotheca will 
set in. Either of these alternatives ma>' be considered as the possible starting point. I do not insist 
that this explanation of the origin of the gonosome in tlie group is the correct one; there is, however, 
nothing to disprove it in the results of investigations made up to date, and it will, if confirmed, alto- 
gether disprove the existence of a difference of principle in the gonosomes, as maintained by Kiihn. 
This proof is thus likewise inadmissible as finalh' disposing of the supposition of a closer relationship 
between Proboscoida and Eiidcndriidcr. 

If we now endeavour, as in the case of the athecates, to sunnnarise the elucidated features 
and previous view's in a key for determination, we must at the outset point out that in this instance 
such a method cannot so easily be employed without reserve, as the transitions in the thecaphores 
are more gradual than in the athecates. An endeavour may nevertheless be made to draw up a scheme 
of the nature indicated. 

I. Polyps with conical, pointed oral part. 

A. The gastral endoderm uniformly developed; polyps and hydrothecne constructed according to a 
radially symmetric ground plan. (Family series Hebellina). 
I. Hydrothecse without opercnla or with a primitive closing apparatus formed from the thinner 

distal part of one side of the h}drotheca. Family LafoeidcE. 
II. Hydrothecae with roof-shaped or conical opercula of composite structure. Family CampanuhmdcB 
B. Gastral endoderm differentiated in heterogeneous parts. 

I. Polyps with fore-stomach and digestive basal stomach parts. (Family series Haleciina). 



HVDROIDA II 



a. Hydrothecse small, radially symmetrical, cannot accommodate the contracted hydranth. Fa- 
mily Haleciida. 

b. Bilaterally symmetrical hydrothecse, with obliquely set diaphragm. 

X. Diaphragm simple. Hydrothecse small, approximately radial structure, generally without 
teeth ; rudimentary or stalked and mobile, two-chambered sarcotheca. Family Plumulariidce. 
XX. Diaphragm generally composed of two obliquely set portions; hydrothecffi markedly 
bilateral, large, most frequently toothed. Sarcothecge all or some one-chambered, sessile 
and immobile. Family Aglaopheniidcr. 
II. Polyps with a basally situate, ventral blind sack with low endoderm cells. Hydrothecae gene- 
rally bilateral. (Family series Sertulariina). 

a. Hydrothecse without opercula. Family SyntheciidcB.. 

b. Hydrothecae with opercular apparatus. Family Scrtulariidm. 

2. Polyps with club-shaped or trumpet-shaped oral parts. (Family series Proboscoida). 

A. Hydrothecse large, radially symmetrical. Family Campannlariidcr. 

B. HydrothecK small, thick-walled, and bilaterally symmetrical. Family SilicitlariidcB. 



II. Thecaphore Hydroids of the Northern Atlantic. 



Family series Hebellina nov. 
Family Lafoeidae. 

Hydrothecse deep bell- to tube-shaped, radially symmetrical after their ground plan, stalked or 
sessile, at times partly fused with the mother tube; diaphragma rarely present. The hydrothecse 
vvitho\il opercula; exceptionally, the distal end of the one wall in the hydrotheca may fold in over the 
aperture. The colonies are stolonial or sympodial. The polyps are radially symmetrical, with conically 
pointed oral part; the endoderm is divided into an oral and a gastral part; the gastral endoderm is 
homogeneous. 

The structure of the polyps gives this family a primitive rank among the thecaphores, and 
among its lowest genera Hcbella must be counted as taking a typical position; this genus is, how- 
ever, especially distributed in the warmer seas. The genus has also been recorded from northern 
waters, although evidently erroneously; its only northern representative should be Ifrbr/la pocillum 
(Hincks) but as it lacks the diaphragm, it cannot be allowed to remain in this genus, and its identity 
will be dealt with later on. 

In course of time, a whole series has been set up with genera of La/oridcr^ and on going 
through the list compiled by Stechow (1913 p. 44) we find that considerable weight is attached to 
the accumulation of the gonangia in aggregates (scapus, coppinia) or their appearing singly. I have 
recently (1917) in studying the coppinia of Gra?ntnarla abictiua, set forth what we know up to the 



HYDROIDA II 



present concerning this distinguishing feature; our knowledge is, in reaHty, so insufficient that the 
greatest care should be exercised in answering for species even where this character has been noted, 
after superficial study, as the only point of difference in comparison with the nearest related species. 
It is clear, that in certain species, the gonothecse of the one sex (the female) appear aggregated as 
scapus or coppinia, while those of the other sex (the male) occur singly. Even though we may not 
at present possess definite proof, it is nevertheless highly probable that also certain Lafo'eida: may have 
unisexual colonies; in such case, however, the occurrence of the gonothecse singly or in aggregates 
will even fail us as a specific character. Obviously then, in the present imperfect state of our know- 
ledge as to the gonangia of the different species, the feature in question must be discarded altogether 
as a eeneric character. Until we know more about the matter, it will certamlv be most correct to 
disregard the question of gonangia entirely when drawing the limitations of the various genera. 



Gen. Lafoea (Lamouroux). 

The colony consisting of upright rhizocaulome formations, or creeping, with tubular or narrow 
bell-shaped hydrotheca:. The hydrothecae are without diaphragma or opercular apparatus, stalked or 
sessile, in the latter case separated from the stolon by a more or less marked constriction; where the 
hydrotheca lies adjoining the stolons, it is possible to distinguish between the wall of the h\-drotheca 
and that of the stolon. 

A whole series of species belonging to this genus have been described from the northern seas, 
and many of them are based on the distinction as to whether the colonies are creeping or upright, a 
character which, as we find on closer investigation, can only be applied with the greatest caution. 
It has long been recognised that Lafoea dniiiosa may either occur as a creeping form, or may form 
upright rhizocaulome colonies; this fact in itself should be sufficient to point the necessity of careful 
consideration, and a closer study of the northern species reveals the fact that one and the same spe- 
cies may at times occur creeping, at others form upright colonies, when some few stolons emancipate 
themselves from the underlayer and thus form a suitable substratum over which other stolons 
may creep. 

Another feature in the Lafoea species which renders their limitation exceptionally difficult is 

their extrordinary power of variation. Such variation is evidently due in part to the influence of 

physical conditions in their environment, which have led to the formation of gigantic arctic forms, or 

heavily built, robust cold-water forms. Critical study of the ver)- extensive material available has tluis 

ed to considerable reduction in the number of species. 

Lafoea dumosa (Fleming) L. Agassiz. 
1828 Campanularia ditnwsa, Fleming, A History of British Animals, p. 548. 
i860 Lafoea dumosa, L. Agassiz, Contributions to the Natural History of the United States, p. 351. 

Colonies creeping or upright, irregularly branched and stiffly built rhizocaulome formations. 
Hydrothecae developed slightly asymmetrically, tubular, with slightly outward curving margin; they 



HYDROIDA II 



are separated by a constriction from the stolons, or may, more rarely, exhibit an indication of stalk, 

forming half a spiral whorl. 

The gonangia are collected in coppinia; with tubes much twisted. The coppinise are herma- 
phroditic, with the male gonothecse wedged in among the female. 

Material: 

"Ingolf St. 6, 63°43' N., i4°34' W.; depth 90 fathoms, 7,0° 

— - 86, 65°03,6' N. 23°47,6' W.; - 76 — (West-Iceland) 
_ - 87, 65°02,3' N. 23°56,2' W.; — no — (West-Iceland) 

"Thor" 63°30 N. 2o°i4' W.; — 80 metres 

Greenland : Sukkertoppen (on Boltenid) (no further data) 
Iceland: Vestmanno depth 28 fathoms 

— Skjalfandi Bay depth 28 fathoms 

The Faroe Islands: 62°29' N., 7°37' W.; depth no metres, 8,71° 

— — 62°i6' N., 6°o6' W.; — no 

— — 7 miles N. by E. of Myggenses point; depth 57 fathoms 
_ _ 6 — N. by W. of Store Kalso; — 60 — 

— — Deep hole at north point of Nolso; — 100 — 

— — Boronass N. 75 W. — 3° — 



'f/:-y> 




J 00 m. 



I'ig. I. Tlie Distribution of Lafora dumosa in the Northern Atlantic. 
In the hatched regions the hterature notes a common occurrence. 



HYDROIDA II 



Some writers unite this species with the two following; this is, however, as I have previously 
shown (igo8 p. 33) not correct. Both iu its creeping form and in the upright colonies it is very typi- 
cally distinct from the remaining northern Lafoea species, partly by its very slightly asymmetrical 
hydrothec;e, which have practically no real stalk at all, partly by the fact that the hydrothec?e, which 
are set very far apart, form almost a right angle with their corresponding stolon. 

The species is widely distributed in the northern seas (Fig. I). It is a distinctly boreal species, 
which can, however, penetrate far into southern waters, and has been recorded, for instance, from the 
Mediterranean (Babic 1910 p. 213). On the other hand, purely arctic conditions seem quickly to set 
a limit to its progress. 

Lafoea gracillima (Alder) Hi neks. 

1856 Cajnpauularia gracillima. Alder, A notice of some new genera and .species, p. 361, pi. 14 figs. 5 — 6. 
1874 Lafoea gracillinia, Hincks, Notes on Norwegian Hydroids from deep-water, p. 132. 
1868 Lafoea pygmaa pars, Hincks, A History of the British Hydroid Zoophytes, p. 205, pi. 40 fig. 3. 
1887 Lafoea fru I icosa pars, Bergh, Goplepolyper (Hydroider) fra Karahavet, p. 334. 

The colony is creeping or upright, with irregularly branched rhizocaulome formation. The 
hydrothecig are narrow, tubular, curved, with the convex side turned upwards; the opening margin is 
on the concave (lower) side never curved outwards, but may be slightly so on the convex side of the 
hydrotheca. The hydrotheca passes gradually over into the stalk, which is of varying length, and 
with a spiral coil closer in some, more open in others. In upright colonies, the stalk axis forms as 
a rule a very acute angle with that of the mother tube, the basal part of the hydrotheca is often 
nearly parallel with the latter. 

The gonothecae are compressed iu hermaphroditic coppinife, the long tubes of which are as a 
rule highly curved. The male gonothecae occur wedged in between the female. 

Forma lypica: finely built colonies, with hydrothecse set wide apart; the hydrothecae entirely 
tube-shaped, with loosely spiral stalk, as a rule with two turns. 

Forma elegaiifula: colonies of coarser build, with closely set hydrothecae; the hydrothecae often 
with the upper part of the opening margin curved slightly outwards; stalk with a varying number of 
mostly close spiral windings. 

Material: 

Forma lypica: 

"Ingolf" vSt. I, 62°3o' N., 8°2i' W., depth 132 fathoms 7,2" 

- - 55- 63=33' N., i5°o2' W., - 

- - 85, 63^21' N., 25°2i' W., 

- - 87, 65°o2,3' N., 23°56,2' W., - 

- 95, 65°i4' N., 3o°39' W., - 

- 127, 66°33' N., 2o°o5' W., - 
Iceland: Skagestrand 

9 miles N.74E. of Hornet, east coast of Iceland, depth 38 fathoms 
62°i7' N., 4°57' W., depth 144 fathoms. 

The Ingolf- Expedition. V. 7. 



316 


— 


5.9' 


170 


— 


— 


no 


— 


— 


752 


— 


2,1 


44 


— 


5,6' 


44 


— 





lO 



HYDROIDA II 



Forma elegantula: 

"Ingolf St 3, 63°35' N., io°24' W., depth 272 fathoms, 0,5° 

- 29, 65°34' N., 54°3i' W., - 68 - 0,2° 

- 31, 66''35' N, 55°54' W., - 88 - 1,6° 

- 33, 67°57' N., 55>' W., - 35 - o-8° 
- - 34, 65°! 7" N, 54° 1 7' W, - 55 - - 

Greenland: Davis Strait (precise locaHty not stated) depth 100 fathoms. 

Akndlek (no further data) 

Egedesminde ( - — — ) 

Mouth of AmeraUkfjord ( - — — ) 

Sukkertoppen, on BoUenia ( - — — ) 

Jakobshavn ( - — — ) 
Hurry Inlet, depth 0—7 fathoms (East Greenland Expedition) 

---57-(- - -) 

Harry Land — 20 — ( — — — ) 

Iceland: "Thor" 52 miles E. of Langanes 
Skjalfandi Bay, depth 28 fathoms 

9 miles N. 7'i.E. of Hornet, east coast of Iceland, depth 38 fathoms 
64°i7,5' N., i4°44' W., depth 40 fathoms, 5,12° 
The Faroe Islands: 6i°4o' N., 7°4o' W., — 135 — 

6 miles N. by VV. of Store Kalso, depth 60 fathoms 
Kara Sea "Dijmphna" (labelled La/oea fruticosd). 

The distinguishing features between Lafoca gracilUina and Lafoca fniticosa may often appear 
very insignificant, and in arctic waters especially one may often be in doubt as to whether a specimen 
is a robustly built colony of I., gracillima forma elegantula or a finely built L. fruticosa forma genuina. 
The feature emphasised by Bonne vie (1899 p. 61) viz: the number of spiral turns on the stalk, is in 
particular extremely variable in somewhat larger colonies, and it is likewise found that the angle 
between stalk and mother stolon, especially among creeping colonies, is little to be relied on. Another 
feature, however, to which I have long since drawn attention (1907 p. 7) seems to be more constant, 
and will also according to the present material serve to determine the identity of species. The feature 
in question consists in tlie fact that the abcauline concave side of the hydrotheca in -Lafoea gracil- 
lima lacks the basal convexity found in Lajoea fniticosa^ and that the margin of the hydrotheca on 
this side is never curved outwards in Lafo'va gracillima, in contrast to La/oea fruticosa , where the lower 
(concave) side of the hydrotheca is thus always more or less S-shaped in profile. 

Among the synonyms for Lafoea gracillima we have also here included Lafoea pygma-a pars. 
Jaderholm (1909 p. 80) includes this species as a synonym under Calycella syringa, and he is un- 
doubtedly right in so doing. According to Hincks (1868 p. 205) the original drawings by Alder 
exhibit indications of opercular formation in the hydrotheca here and there, a point which beyond question 
suggests this species. On the oilier hand, Hi neks' s description is entirely in agreement with the 



HYDROIDA II 



II 



creeping colonies of Lafoea gracillii>ia^ and a number of colonies which have later been identified as 
Lafoea pygmcBa should doubtless be referred to Lafoea gracillima. Bonne vie, (1899 p. 62) notes in 
her table as to the hydrothecce that they have "slightly outward-curving margin"; this does not agree 
with Hiucks's expression "hydrothecje . . . cylindrical, elongate and narrow" or with his drawing of 
the species. In ray first report on the hydroids from "Michael Sars" (1903 the table) I recorded Lafoea 
pygmcea from several localities, giving also a drawing of the coppinia of the species; subsequent revi- 
sion of the material has shown me that the specimen indicated is, like most of the others, a typical, 
creeping Lafoea gracillima, while some few colonies are creeping Lafoea dniiiosa. Lafoea pygnura must 




__, . 600m, 



Fig. II. Localities of Lafoi'a gyaciUima forma typica • and forma elegantula -j- in the northern Atlantic. 

In the hatched regions the hteratnre denotes a common occurrence of the species. 

(The dates from British seas are incomplete on account of a general confusion with Lafoi'a fmlicosa). 

thus mainly be regarded as .synonymous with Lafoea gracillima and Calycrlla syringa, and can accor- 
•^ingly no longer be counted as an independent species. 

Lafoea gracillnna appears in two forms, affording parallels to those of the following species. 
The finely built forma typica is quite cosmopolitan in its occurrence, and has been met with in all 
seas from pole to pole. In arctic — and as far as can be seen also antarctic — waters, there has also 
developed, in addition to forma typica^ a more robust and closely built forma eleganfula, the stalk of 
which generally commences with a single loose winding, continuing then in a varying number of 
close turns. Forma eleganhtla is, as mentioned, arctic, but may (text fig. II) also at times penetrate 
into boreal waters. 



J2 HYDROIDA II 



Lafoea fruticosa M. Sars. 
1851 Campanularia fruticosa, M. vSars, Beretning om en i Sommeren 1849 foretagen zoologisk Reise, 

p. 131, 138. 
1863 Lafoi-'a fruticosa, M. Sars, Bemserkninger over fire norske Hydroider, p. 30. 
1868 — pociUum, Hincks, A History of the British Hydroid Zoophytes, p. 204, pi. 40, fig. 2. 
1874 — grand is, Hincks, On deep-water Hydroida from Iceland, p. 147, pi. 6, figs. 1 — 2. 
1899 — symmetrica, Bonnevie, Norske Nordhavs-E-xpedition, p. 64, pi. V, figs. 2 c and 4. 

The colonies are creeping, or form upright, irregular rhizocaulomes. The hydrothecse are cylin- 
drical or narrowly bell-shaped, more or less asymmetrically developed or slightly curved, the one side 
as a rule curving somewhat more markedly outwards than tiie other. The hydrothecse have as a rule 
a slightly expanded basal part and a more or less outward curving opening margin, they are sharply 
marked off from the stalk, which is of varying length, spirally turned, or less frequently divided into 
rings. The stalk itself forms, in the upright colonies, an open angle of 45° — 80° with the mother tube. 

The gonothecse are gathered in hermaphroditic coppiniae, the tubes of which are as a rule 
highly curved. The male gonothecse are wedged in among the female. 

Forma germina: finely built colonies, always with asymmetrical, narrow hydrothecte, the stalk 
forming an acute angle with the mother tube. 

Von\\2igrandis: coarsely built colonies with wide cylindrical to narrowly bell-shaped hydrothecas; hy- 
drothecse often almost or entirely symmetrical, the stalk generally forming a more obtuse angle with 
the mother tube. 

Material: 

Forma genicifia: 

"Ingolf St. 34 65°i7' N., 54°i7' W., depth 55 fathoms 

- - 86 65°o3,6' N., 23=47,6' W., _ 76 - 

- - 87 65°o2,3' N., 23°56,2' W., - no - 
"Thor" 65°52' N., 23°58' W., - 62 metres 

6i°o7' N., 9>' W., - 835 - 

Greenland: Egedesminde (no details noted) 
Proven ( - — — ) 

Cape Tobin, depth 57 fathoms (East Greenland Expedition) 

Mouth of Hurry Inlet, — 50 — ( — — — ) 

Iceland: Skjalfandi Bay, depth 28 fathoms 

9 miles N. 74 E. of Hornet, east coast of Iceland, — 38 — 
The Faroe Islands: 7 miles N. by E. of Myggena;s, — 57 — 

Forma grandis: 

"Ingolf St. 2 63=04' N., 

- - 4 64=07' N., 

- - 34 65°! 7' N., 

- - 95 65°i4' N., 



9"22' 


w.. 


depth 262 fathoms 


5.3' 


II°I2' 


w., 


- 237 - 


2,5' 


54°i7' 


w., 


- 55 — 


— 


3o°39' 


w., 


- 752 — 


2,1' 



HYDROIDA II J, 



Greenland: Egedesminde, depth 30—40 fathoms 

Sukkertoppen, on Boltruia (no details noted) 

Ingmikertok, Angmagsalikfjord (depth not given) (East-Greenland Expedition) 
Iceland: 33 miles SE. '/^ E. of Stokkesntes near Horns vig, depth 84 fathoms (labelled Lafoea 
fniticosd). 

We have here a species of highly variable character, especially in the northern waters, where 
the biophysical factors evidently exercise an important and determinative inflnence upon the variation 
of the species. There is consequently also much confusion as to the synonymy of the species. La/oea 
fruticosa was estabHshed by M. Sars (1849) and in his description we find the following with regard 
to the hydrothecse: "superne latioribus, inferne coarctatis". This certainly gives the impression of a 
hydrotheca having its lower portion, partly on account of the curvature of the wall, broader than the 
upper, which again expands nearer the opening. The same is also seen in the drawing subsequently 
given by G. O. Sars (1873 Tab. IV, figs. 17 — 18) of the species, undoubtedly based upon M. vSars's 
type specimens. This does not agree with the statements of Bonne vie (1899 p. 65) and we can 
hardly help feeling that among Bonnevie's Lafoea fruticosa there must also be some colonies of 
La/oea gracillhna forma elegaiitiila; a supposition which is, moreover, confirmed by the study of her 
material in Christiania. On the other hand, Bonnevie has (I.e.) established an entirely new species, 
La/oea symmetrica^ which as a matter of fact is based upon variants of La/oea /ruticosa. The principal 
difference between Lafoea /ruticosa and La/oea symmetrica is, according to Bonnevie, the fact that 
the latter species has symmetrical hydrothecae, whereas these are of asymmetrical structure in the 
former. It will be seen, however, from the drawings of hydrothecte given (1899 Tab. V, fig. 2 c') that 
asymmetrical hydrothecse can also occur in Lafoea syvimctrica. On the other hand, further examina- 
tion of the hydrothecae in La/oea /ruticosa (cf. Broch 1908 fig. 4, 1909 textfig. 19) shows that the asymmetry 
is often but very slightly pronounced, and even disappears altogether in a greater or lesser percen- 
tage of the hydrothecse in a fairly large colony. We find, in other words, that in this respect, every 
imaginable transition form may be met with from La/oea fruticosa to La/oea syi>ni/ctrica\ the character 
in question is therefore not suitable for purposes of specific distinction. There remains then, the size, 
which is said to differ as between Lafoea fruticosa, L. symmetrica, and L. graudis. It is soon found, 
however, that this character likewise is here unserviceable. On the one hand, the three species form, 
according to Bonnevie, a finite series of sizes, La/oea symmetrica being from the drawings and de- 
scription, larger than La/oea fruticosa, but smaller than La/oea grandis. On the other hand, a large 
material of the three forms reveals the fact there is no discernible interval throughout the series; all 
intermediate stages are found, from finel)- built colonies of Lafoea /ruticosa to such extreme cold-water 
variants as those upon which Hincks's L^/o'ea graudis is based. We are thus compelled to include 
the forms under one species, the correct name of which .should be Lafoea /ruticosa. 

The amalgamation of these three species into one. however, involves the further abolition of 
La/oea pociltum Hincks (1868 p. 204, pi. XL, fig. 2). The shape of the hydrothecse is very correctly 
described by Hincks as follows: "tumid below, with the sides curved inwards above, and expanding 
again .slightly towards the top". This coincides entirely with M. Sars's "superne latioribus, inferne 
coarctatis". The length of the stalk in La/oea species and its spiral winding or division into separate 



14 



HYDROIDA II 



rings varies even within a single large colony to such a degree that the features in question cannot 
be taken as distinctive specific characters, unless combined with others more sound. There remains 
then the creeping form of colony. But Lafom fruticosa here differs iu no wise from the remaining 
species of the genus; its colonies may be pure upright rhizocaulome formations, but this is very rarely 
the case. Generally, the somewhat larger colonies consist partly of upright, partly of creeping por- 
tions, and it is very common to meet with such composite colonies, when they are brought up with 
the underlaver attached. Exclusively creeping colonies thus merely form the other extreme in the 




. b Qo m. 



Fig. III. The distribution of Lafoi-'a fruticosa forma genuina • and fonna gramiis -\- in the northern Atlantic. 

The hatched region denotes a common occurrence of Lafoea frtUicosa according to Uterature. 

(In British waters the dates are to be revised owing to confusion of the species with Lafoea gracillima). 

same series of variants. Consequently therefore, Lafoea pocillum must be discarded, as being synony- 
mous with Lafoea fruticosa. 

Jaderholm (1909 p. 71) follows, stating no particular reason, the example of Nutting (1901 
p. 175) and ascribes Lafoea pocillum to the genus Hcbclla. Nutting, in his diagnosis of this genus, 
states as follows: "Hydrotheca; . . . having their cavities separated from those of the stem by a partial 
septum". Such septum or diaphragm is altogether lacking iu the European specimens of Lafoea 
pocillum. 

It must not be forgotten, however, that the former species partly owe their existence to external 
determining factors. Disregarding the creeping form of colony as opposed to the upright, the differ- 
ences presented by the colonies in a less extensive material are considerable enough to warrant at 
any rate temporary distinction of species, and it would in these cases be incorrect not to notice the 



HYDROIDA II jc 



same. Such "species" will on further investigation often be found to represent regular groups of vari- 
ants. And this is precisely the case here. In Lafom fniticosa, the transition forms are not infrequent 
in boreal waters, and it may often appear doubtful where the limits should be drawn. It is perfectly 
admissible, in the case of La/oca fruticosa^ to distinguish between a forma iioniina as opposed to forma 
graudis, the first-named comprising that group of variants hitherto indicated as Lafom Jruticosa, and 
the latter embracing the species Lafoea graiidis and Lafoea syiiunetrica. The two forms also make 
typical geographical groups. 

Forma gemiina^ which must be regarded as the mother form, is of very wide distribution; it 
is encountered together with the following form (text fig. Ill) in the arctic region, and alone in boreal 
and southern waters, both in the Atlantic and the Pacific, where it has been met with so far down 
as Hawaii. Intermediate forms are, as mentioned, frequently found in boreal and arctic waters, more 
particularly in the transition zones between the two. 

Forma gra>idis is of strictly arctic occurrence, and must here be regarded as a typical character 
form. Billard's record (1907 p. 176) of a find at Cape Spartel must, from the measurements and 
figures given, be due to incorrect diagnosis. 

Gen. Toichopoma Levinsen. 

The colonies are creeping, or form upright, irregularly branched rhizocaulomes, with stalked, 
cylindrical hydrotheca;. The hydrothecse lack the diaphragm, but have a primitive closing apparatus; 
the distal integral part of one side of the hydrotheca wall can be closed down over the aperture. 

Toichopoma Obliquum (Hincks) Levinsen. 
1874 Calycella obliqita, Hincks, On deep-water Hydroida from Iceland, p. 149, pi. 6, figs. 4 — 5. 
1893 Toichopoma ohl/ijtiuiii, Levinsen, Meduser, Ctenophorer og Hydroider, p. 178. 

191 1 — — Kramp, Report on the Hydroids, p. 374, pi. XX, fig. 4, pi. XXIII, fig.s. 5—8, 

pi. XXIV, fig. I. 

The colonies are creeping, or form upright irregularly branched rhizocaulomes. The hydrotheca; 
have a short stalk with a varying number of spiral windings; they are cylindrical, curved, with an 
adcauline convexity, as a rule somewhat expanded near the base, and slightly broader again near the 
aperture, which in open hydrothecce is somewhat asymmetrical; the hydrotheca passes gradually over 
into the stalk. The abcauliue distal part of the aperture is thin, and can be closed in towards the 
opposite wall over the contracted polyp. 

The gonothecas are closely packed in a (hermaphroditic?) coppinia on stem or branches; the 
single gonothecae are pentagonal or hexagonal, with a short, narrow cylindrical neck. Between the 
gonothecas are inserted long, highly curved tubes, forming a close network over the coppinia. 
Material: 

Greenland : Jakobshavn (no details noted) 
Egedesminde ( - — — ) 

Toichopoma obliquum is a high arctic species, recorded both from West and East Greenland, 
as well as from Spitzbergen and the Murman Sea. 



i6 



HYDROIDA II 



Gen. Grammaria (Stimpson). 

Colonies creeping or forming upright, irregularly branched rhizocaulomes with sessile, cylin- 
drical hydrothecK, which are to a varying extent fused with the tubes, so that in this part it is im- 
possible to distinguish between the wall of the hydrotheca and tube. The hydrothecse can at times 
exhibit a basal constriction forming a boundary between them and the mother tube, but such con- 
striction may also often be wanting. Diaphragm and operculum lacking. 

In earlier works, the creeping species have been incorrectly noted as a separate genus, Filelhim. 
The type of this genus was Filcllum serpens (Hassall). I have previously (1912 p. 10) pointed out 
that this species should be classed under Graj>iniaria, and ^m supported here by Kramp (1914 p. 
1030). Further proof is afforded by Stechow, who describes (1913 p. 118) a species Grammaria 
scandeus, with both creeping and upright colonies; it would seem doubtful whether this species should 
properly be maintained beside Grammaria abieiina, which may often be found in Throndhjem Fjord 
in the same manner. Stechow (1. c. p. 121) considers, however, that the genera should be maintained, 
"da ihre Beibehaltung eine grosse Bequemlichkeit fiir die Bestinimung ist". 



Grammaria serpens (Hassall) Broch. 
1848 Campamilaria serpens^ Hassall, Catalogue of Irish Zoophytes, p. 2223. 
1868 Filellmn serpens^ Hiucks, A History of the British Hydroid Zoophytes, p. 150. 
191 2 Grammaria serpens, Broch, Hydroida from the "Michael Sars", p. 10. 

Colonies creeping. Hydrothecce cylindrical, bent to an angle, the basal part fused with the 
stolon. The hydrotheca is tubular, quite cylindrical, or with slightly outward curving opening margin; 
the transition to the stolon is as a rule marked by a slight constriction. 

The gonothecse are collected in close coppiniae, with highl\' curved tubes. They are herma- 
phroditic, with the male gonothecse wedged in between the female. 

Material : 

"Ingolf St. 87 65"o2,3' N., 22°56,2' W., depth no fathoms 

"Thor" 64°i6' N., 22°I7' W., — 50 metres 

- 64°o2' N., 22°33' W., - 34 - 

— 63^30' N., 20° 1 4' W., — 80 — 
Greenland: Egedesminde (without further details) 

Store Hellefiskebanke ( — — — ) 

Davis Strait ( — — — ) 

Iceland: Vadlevik, depth 80 fathoms 

33 miles SE. of Stokkesnaes near Hornvig — 84 — 
g'/j — S. by W. '/s W. of Ingolfshofdi, depth not given 
The Faroe Islands: 8-10 miles N. of the Faroe Lslands (without further details) 
7 miles N. by E. of Myggenaes point, depth 57 fathoms 



HYDROIDA II 



17 



6 miles N. by W. of Store Kalso depth 60 fathoms 

Deep hole at north point of Nolso — 100 — 

Boronaes H/^ miles in N. 75 W., 

5 miles SSE. of Bispen 

13 — W. by S. of Munken 

Stokken 2 miles in S. 22 E. 



— 30 - 

— 50 - 

— 150 — 

— 55 — 



This remarkable species was formerly considered as the type of the genus Filelhim. Bonne- 
vie (1899) notes it under Lafoea^ but it should, as I have indicated above, be classed under the genus 




200 m. 



600 m. 



Fig. IV. The occurrence of Grammaria serpens in the Northern Atlantic. 
In the hatched regions the hterature notes a common occurrence. 

Graniniaria. From the records, the species is of highly cosmopolitan distribution; it is less numerous, 
however, in the arctic seas, and is likewise not altogether of common occurrence in warmer waters. 
It is most frequently met with in the mid-littoral parts of the boreal region (fig. IV) and is here but 
rarely found at greater depths. 



Grammaria conferta (Allman) Broch. 

1877 Cryptolaria conferta. Allman, Report on the Hydroida of the Gulf Stream, p. 17, pi. 12, figs. 

6 — 10. 
191 2 Granuna-^ia conferta., Broch, Hydroida from the "Michael Sars", p. 10. 

Upright, irregularly branched rhizocaulomes, the outer ramifications monosiphonic, the basal 

The Ingolf-Expedition, V. 7. 3 



jg HYDROIDA II 



parts polysiphonic. Tlie hydrothecEE are arranged on the branches and stem in two opposite rows, 
alternating, with the mouth turned now to one side, now to the other. The hydrothecse are large, 
tubular, passing by a slightly marked constriction over into the stolon; the diaphragm is lacking. In 
its proximal part, the hydrotheca is fused with the stolon; owing to a sharp bend in the hydrotheca, 
the distal part is almost perpendicular to the proximal. Opening margin slightly everted. 

The gouothecse are set close together in a (hermaphroditic?) scapus (without inserted tubes) on 
the branches or stem. The gonothecse are bottle-shaped, with a short neck. 



Material: 














"Ingolf St. II 


64°34' N., 


31° 1 2' W., 


depth 


1300 


fathoms 


1,6^ 


- - 31 


66°35' N., 


55°44' W., 


— 


88 


— 


1,6° 


— - 32 


66°35' N., 


56=38' W., 


— 


318 


— 


3,9° 


- - 78 


6o°37' N., 


27°52' W., 


— 


799 


— 


4,5° 


— - 92 


64-44' N., 


32°52' W., 


— 


976 


— 


1,4° 



In a previous work (191 2 p. 10) it was pointed out that Cryptolaria confer ta is distinguished 
from the remaining Grammaria species only by differences so slight that they do not by any means 
warrant generic separation; the bilateral arrangement of the hydrothecse is not an adequate generic 
character. — Interesting from a biological point of view is the fact that this typical deep-sea form as 
a rule developes fiUform, root-like basal offshoots, for attachment to the soft bottom; I have, however, 
once seen a colony which had attached itself to a fragment of the shell of a deep-water mollusc, and 
had in consequence less highly developed offshoots than most colonies otherwise have. 

Grammaria confertds northern limit of occurrence is moved a considerable distance farther north 
by the latest finds; otherwise, its distribution is that of a typically abyssal form, and the record of 
its occurrence in only 88 fathoms' depth far up in Danmark Strait thus comes as a surprise; the more 
so since the species should generally be noted as a character form for the warmer and deeper waters 
of the Atlantic. It does not penetrate in over the submarine ridges which form the southern boundary 
of the Norwegian Sea. 

Grammaria abietina (M. Sars) Stimpson. 
1851 Campanularia abietina^ M. Sars, Beretning om en i Sommeren 1849 foretagen Zoologisk Reise, p. 131. 
1854 Grammaria robiista, Stimpson, Synopsis of the Marine Invertebrata of Grand Manan, p. 9, pi. i, 

fig- 3- 

The colonies form coarsely built, stiff, irregularly branched rhizocaulomes, in exceptional cases with 
creeping portions. The hydrothecse lack the diaphragm, and pass over without constriction into the 
mother tube; their lower limit is formed by the ring of small chitinous bodies to which the base of 
the hydranth is attached. The hydrothecse are tubular, bent to an angle, and have as a rule a slightly 
everted opening margin. The plane of the aperture itself is normally parallel with the axis of the 
branch; in forms with particularly short hydrothecse, the aperture is slightly turned upwards. The 
hydrothecse project in most cases far beyond the secondary tubes. 

The gonothecct are closely collected in hermaphroditic coijpinitc with highly curved tubes. The 



HYDROIDA II 



'9 



;erial: 








Forma typica: 






"Ingolf" 


St. 


34 


65°i7' N, 


— 


- 


51 


64° [5' N, 


— 


- 


87 


65°02,3'N., 


— 


- 


92 


64°44' N, 


— 


- 


95 


65°i4' N., 


— 


- 


98 


65-38' N., 


"Thor" 






66°43' N, 



68 


- 7,32' 


no 


— 


976 


14' 


752 


- 2,1' 


138 - 


5>9' 


48 - 


— 



female gonothecae are much compressed, sessile; the male are stalked, with the stalks pressed in among 
the female gonothecre. There are onh- a small number of almost spherical male gonotheCcC in the 
coppinia; they are freely placed between the surface of the female aggregate and the outer coils of 
the tubes. The female gonophores are heteromedusoids; the male reduced cryptomedusoids; the fertile 
colony has nematocysts dimorphously developed. 

Forma typica: The upper (adcauline) wall of the hydrotheca proiects 1,5—3 times the diameter 
of the aperture beyond the tubes; the plane of the aperture is parallel with the axis of the branch. 

Forma hrevicyatha: the free portion of the adcauline wall is 0,5 — i times the diameter of the 
aperture; the aperture itself is turned obliquely upward. 



54°i7' W., depth 55 fathoms 
I4°22' W., 
23=56,2' W., - 
32°52' W., 
3o°39' W., 
26° 2 7' W., 
i5°03' W., 

Greenland: Davis Strait, depth 66 fathoms (without further details) 
Sukkertoppen, on Boltenia ( — — — ) 

Godthaab, depth 50—60 fathoms 
Hunde-Eiland (without further details) 

Cape Tobin, depth 57 fathoms (East-Greenland Expedition) 
Jan Mayen: 70=32' N., 8°io' W., depth 470 fathoms 
Iceland; 4 — 5 miles E. of Bakkefjord, — 70 — 

5 miles E. of Seydisfjord, — 135 — 

64°27' N., 13=27' W., — 150 metres 

The Faroe Islands: 61=40' N., 7=40' W., — 135 fathoms 

6 miles N. by W. of Kalso, — 60 — 
Forma brevicyatha: 

The Faroe Islands: 7 miles N. by E. of Myggenaes point, depth 57 fathoms 
6 _ N. by W. of Kalso _ 60 — 

A rich and well-preserved material of Grammaria abirtinn from the Trondhjem Fjord afforded 
an opportunity for further study of the species. Its polyps have an oral part with mainly indifferent 
endoderm cells above the tentacle whorl; the true gastral endoderm exhibits an altogether uniform 
development. The base of the hydranth is fastened to the wall of the h\-drotheca far in between 
the tubes of the rhizocaulome, by a wreath of small chitinous bodies; this is the only discernible limit 
between the hydrotheca and its mother stolon, which are otherwise practically of equal breadth. A 
study of the coppinia (Broch 1917) brought to light several peculiarities. In fertile colonies we find, 

3* 



20 



HYDROIDA II 



in 



the defensive polyps and elsewhere, large, practically cylindrical nematocysts in addition to tlie small 
capsule form which is found in all thecaphores; the nematocysts are thus dimorphous. A remarkable 
feature about the coppinia is the position of the male gonothecEe, which here appear as stalked, oval 
to spherical formations between the closely packed female gonothecse and the outer protective network 
of the tubes. Grammaria abietina thus presents an intermediate stage between types with uniform, 
hermaphroditic coppiuise, where the male gonotheca; are wedged in among the female, and those 
where the male gonothecae appear singly outside the coppinia or scapus, which has become an alto- 
o-ether female aggregate. The gonophores in Grammaria abietina exhibit distinct sexual dimorphism; 
the female gonophores are heteromedusoids, the male cryptomedusoids. The cryptomedusoid gono- 
phore is, however, here highly reduced, and distinctly presents a transition stage which would, on 

slight further reduction, become a styloid gonophore. 

From two places at the Faroe Islands we have in the material .some very 
richlv developed colonies which, owing to the somewhat divergent character 
of the hydrotheca, are here noted as representatives of a particular form, 
forma brcvicyatlia nov. In point of habitus, the mentioned colonies differ 
but little from forma typica, they are of equally robust build, and with the 
same rich ramification; on closer examination, however, one cannot fail to 
observe the remarkable short hydrothecse (fig. V). In forma typica^ the 
hydrotheca protrudes its distal parts out in front of the stolons so far that 
the free portion of its upper (adcauline) wall reaches a length of 1,5 to 3 
times the diameter of the aperture; in forma brevicyatlia^ow the other hand, 
the corresponding part is only one-half to one diameter in length. This 
might perhaps by some be regarded as a good specific character. We find 
however, here and there among the colonies, h\drothecse presenting the same 
features as forma typica ^ and, in slightly greater numbers, intermediate 
forms with lengths filling the interval between the dimensions named. On 

Fig. V. Grammaria abietina 

forma brevicyatha. Terminal the Other hand, these intermediate forms, and ^Hypica''^ hydrothecae occur 
part of of a branch. Colony ^. j^^ ^^ ^\-^„\^i a percentage among the colonies that they exert no influ- 

fromvmiles N.byE.ofMygge- .? to i' & & J 

n:t,s point, the Faroe i.siands, euce upoii the general character of the colony as a whole. How far we have 

57 fathoms. (X 4".) , ,,-,,, . , i • 1 -.i , • .l 

here to deal with a local variant group, cannot be determined with certainty; 

that the form can hardly be very common in the northern seas is evident from its rare occurrence 
in the extensive material now being dealt with, even wlien this is supplemented by the large collect- 
ions from Trondhjem Fjord. Still, the form in question cannot be summarily disposed of by noting 
it under the head of casual single variants, since it occurs in a single colony from one place, but in 
four remarkably luxuriant ones from the other. 

Forma brevicyatha exhibits certain resemblances to Grammaria i^nmersa Nutting; there are, 
however, so considerable differences observable that the two cannot be confused. The latter species is 
immediately recognisable from its finer structure, whereas Grammaria abietina is a species of very 
coarse build. The splitting of the tops of the branches (fig. V) in forma brcvicyatlia also agrees 
with Grammaria abietina^ as distinct from Grammaria immersa. A certain likeness to the latter species 




HYDROIDA II 



21 



again, we find in the shape of the hydrotheca; according to Krani]), (1911 p. 376) the margin of the 
liydrotheca in CraiiDiiaria abirtina — in contrast to Grammaria i»imcrsa — always curves outwards 
slightly; in forma brevicyatha^ on the other hand, this is only cpiite exceptionally the case, and by far 
the greater number of hydrothecfe show no indication of outward curvature in the margin. Kramp 
has (1. c.) pointed out another feature which is here of more importance. In forma brcvicyatha^ the 
hydrotheca aperture is almost invariably turned somewhat obliquely upward.s, not as in forma typica^ 
where the plane of the aperture is parallel with the axis of the branch, or in Graminaria immersa, 




Fig. VI. Localities of Giainmana abietina (forma brcvicyatha -|-) in the Northern Atlantic. 
In the hatched region the literature notes a common, although scattered occurrence. 

where the opening is even turned slightl>' downwards. In forma brcvicyaf/ia, only the few large hydro- 
thecse have a plane of aperture parallel with the axis of the branch. 

Grainiiiaria abietina is a t^■picaI arctic-boreal species, recorded also in a single instance (Bil- 
lard, 1904 p. 164) from the north of France. It may at times penetrate down to great depths, as for 
instance at the "Ingolf St. 92, where it reached 976 fathoms, the greatest depth hitherto recorded for 
this species. Otherwi.se it is chiefly found (see fig. VI) in the deeper parts of the littoral regions of the boreal 
and arctic area. Grammaria abicfiita is also apparently an Atlantic species; it is known from the east coast 
of North America, to Taimur, but has not hitherto been recorded from about Bering Strait or the 
Pacific. If, however, it should prove correct that Grammaria scandens Stechow is a synonym for 
Grammaria abietina, then it must be classed among the circumpolar species. 



22 HYDROIDA U 



Grammaria immersa Nutting. 
1901 Grammaria imviersa. Nutting, Papers from the Harrinian Alaska Expedition, p. 178, pi. XXI, 

figs. 5, 6. 

The colonies form stiff, but finely built, irregularly ramified rhizocaulomes. The hydrothecse 
pass over into the stolon without marked constriction, their basal limit is formed by the series of small 
chitinous bodies to which the base of the hydranth is attached. Diaphragm lacking. The hydrothecjE 
are tubular, highly curved in the distal part, and with no outward curvature of the opening margin. 
The aperture is normally turned somewhat obliquely down; more rarely, we may find the plane of 
the aperture parallel with the branch axis. The short freely projecting part has an upper (adcauline) 
wall in front of the stolons, its length being almost invariably less than half the diameter of the 
aperture. 

The gonothecse are collected in close (hermaphroditic?) coppinise, the tubes of which are highly 
curved, making a close network outside the gonothecse. 

Material : 

Iceland: 8 miles E. of Seydisfjord, depth 60 fathoms (labelled Grammaria abietina). 

Grammaria immersa is an arctic character species; only quite exceptionally does it seem to 
penetrate into the boreal regions. It is circuinpolar, and belongs to the littoral region. 



Gen. Lictorella (Allman). 

Upright colonies with sympodial growth. The hydrothecae deep bell-shaped to tubular, often 
exhibiting a slight asymmetrical development; they have a low yet strong diaphragm, but lack opercular 
apparatu.s. Nematotheca; and nematophores lacking. Gastral endoderm of the polyps uniformly 
developed. 

Lictorella pinnata (G. O. Sars) Allman. 
1874 La/oea pinnata, G. O. Sars, Bidrag til Kundskaben om Norges Hydroider, p. 94, tab. 4, figs. 25—28. 
1874 — halecioides, Allman, Report on the Hydroida .... Porcupine, p. 471, pi. 66, figs, i, i a. 
1888 Lictorella halecioides pars, Allman, Challenger Report vol. XIII, p. 35. 
nee 1907 Lafoea pimiafa, Browne, Hydroids collected by the "Huxley", p. 25. 

Upright, single or double pinnate colonies, generally in one main plane, with polysiphonic 
main stem. The hydrothecse alternating in two rows along the branches, with a tendency to unilateral 
arrangement; the hydrothecse all turned obliquely forward towards the one side (front) of the colony. 
The hydrothecse are narrowh- bell-shaped, with slightly everted opening margin; transition to stalk 
gradual. The hydrotheca has a low but strongly developed diaphragm. Stalk generally short, with an 
oblique furrow on the upper side, at times also a furrow running right round the stalk lower down. 
The latter furrow runs transversely to the stalk. Polyps with uniform gastral endoderm. 

The gonothecse are collected in an openly constructed scapus on the stem or main branches. 



HYDROIDA II 



23 



The single gonothecce are reversed, narrowly conical to almost c\lin(.hical, fastened to the hydrocaulus 
bv a rndimentarv stalk at the narrow end; distally, the\- are furnished with three, more rarely with four 
or two, round lateral openings, each with a short neck. 

Material: 

"Ingolf" St. 7 63°i3' N., i5°4i' W., depth 600 fathoms 4,5° 

- - 25 63>' N., 54°25' W., - 582 - 3,3° 

- - 81 6i'^44' N., 27°oo' W., — 485 — 6,1° 
"Thor" 6i°i5' N., 9=33' W., — 872 metres 

Levinsen (1913 p. 287) believes to have found a blind sack in Lictorrlln pimia/a; this must 
doubtless be due to an accidental S-shaped curvature of the polyp, which would not, however, produce 




....-.- boat 



Fig. Vll. Fiuds of Lictorella pinnata iu the Northern .Atlantic. 

a blind sack of any real anatomical importance. Microtome sections reveal an entirely uniform gastral 
endoderm, and I have not been able to find any portion of the endoderm histologically corresponding to 
the epithelium in the blind sack of Sertulariidcr. The "blind sack" observed must thus be due to accident. 
Lictorella pinnata exhibits a highly remarkable distribution (fig. VII). It belongs to the 
upper part of the abyssal region, but penetrates as far down as 1300 metres; on the other hand, the 
species can at times occur right up in the littoral region, and has been met with m the Hardanger 
Fjord even up at a depth of only 90 metres. Horizontalh-, the species seems to be quite widely distri- 
buted, but the few records from southern seas are unreliable, as the species has here been confused 
with Lictorella autipathes (Lamarck). Pictet and Bedot (1900 p. 16) record it from the Bay of Gas- 



^. HYDROIDA II 

24 



cogne. Browne's specimens from the Bay of Biscay (1907 p. 25) on the other hand, should not be 
included here; from the nematothecse, they should be ascribed to Zygophylax, and are plainly identical 
with the following species. In the northern Atlantic regions, the species appears to follow the warmer 
water-masses in their progress through the boreal regions; it has exceptionally been found right up 
in the Barents Sea. 

Gen. Zygophylax Quelch. 

Upright colonies with sympodial growth. The hydrothecse are narrowly bell-shaped to tubular, 
not infrequently somewhat asymmetrical in structure, with a low, but strongly developed radially 
symmetrical diaphragm. The colonies are furnished with small nematothecfe. The polyps have a uni- 
formly developed gastral endoderm. 

Zygophylax biarmata Billard. 

1906 Zygophylax biarmata, Billard, "Travailleur" et ''Talisman", p. 180. 

1907 Lafoea pinnata, Browne, Hydroids collected by the "Huxley", p. 25. 

191 1 Lidorella Levinsem, Saemundsson, Bidrag til Kundskaben om de islandske Hydroider II, p. 86. 
nee 1913 Zygophylax biarmata, Stechow, Hydroidpolypen der Japanischen Ostkiiste, p. 114. 

Colonies upright, in a plane singly or doubly pinnately branched with polysiphonic main stem; 
the branches nearly regularly alternating. The hydrothecse are alternately placed, turning obliquely 
forward towards the one side (front) of the colony; i. e. with a tendency to unilateral arrangement. 
The hydrothecse are mainly tubular, with slightly outward curving margin, narrowing evenly down- 
wards to a stalk of varying length, which has one or two more or less distinctly marked segmenta- 
tions. The hydrotheca has a well developed low diaphragm. At the base of the hydrotheca stalk, 
and occasionally elsewhere on the tubes, there are small, cylindrical nematothecae, attached to the tube 
or apophyse by a short and often indistinct stalk, generally in one piece. The apophyse has normally 
a couple of nematothecse. 

The gonothecse are collected in a primitive, open coppiuia (hermaphroditic?) on the stem or 
main branches; the nematothecse are more richly developed in the gonotheca aggregate than elsewhere, 
and appear there in large numbers. The gonothecse are flattened ovate, with an outward and down- 
ward curving neck distally on either side in the transversal plane. 

Material : 

Iceland, near Vestmanno, depth 510 metres. (T)-pe specimen of Licforrlla Levinscni). 

The first description of this remarkable species is that given by Billard (1906 p. 180) who 
had, however, only sterile colonies to go upon. It is undoubtedly the same species which Browne 
records (1907 p. 25) from the Bay of Biscay, though he ascribes it incorrectly to Lafoea pinnata G. O. 
Sars; the nematothecse show that it must be a Zygophylax,^ and the exhaustive description very di- 
stinctly suggests Zygophylax biarmata. Sacmundsson (1911 p. 86) describes the species anew under 



HYDROIDA II 25 



the name of Lictorella Levinsem, and notes the nematothecie as among its characteristic features; his 
colonies, which I liave had an opportunity of examining, are fertile, wherefore he was also able to 
describe the gonosome. This is of a highly peculiar character, and at once demonstrates the incorrect- 
ness of Stechow's supposition (1912 ^. 114) that the species should be identical with Zygophylax 
arntata (Ritchie). Ritchie's species {1907 p. 533) has a typical coppinia, the tubes of whicli are each 
furnished with several nematotheca;. 

The single gonothecse in Zygophylax biariiiata resemble not a little tliose of Lictorella pinnata^ 
the number of opening tubes, however, being apparentl}' in Zygophylax biarwata constantly reduced 
to two, the tubes being at the same time somewhat longer. The single gonotheca stands out freely, 
but the gonothecse are closely packed in clusters on the stem or main branches, and between them 
we find numerous long nematothecae, remarkably well developed, so that the whole aggregate must 
be regarded as a primitive coppinia, or rather as something between the open scapus and the coppinia. 

There are one or two points which seem to count against the identity of Lictorella Levinseni 
and Zygophylax biarntata. Seem und sson's description rather gives the impression that there are 
not, normally, a pair of nematothecce on the apophysis; on closer investigation, however, we are led 
to the conviction that there are, as a rule, a couple of holes in the periderm showing that nemato- 
thecae have been there, but have fallen off. The colony investigated is the same which Scemunds- 
son shows in fig. 2 a. — A further difference would seem to exist in the hydrotheca stalks, which in 
Ssemundsson's specimens are somewhat longer in proportion than stated by Billard. The length 
of stalk, however, varies considerably in hydroid species, and cannot thus be used as a specific char- 
acter. And finally, the hydrothecse in the colony here concerned exhibit a tendency to unilateral 
arrangement Scemundsson does not mention this feature, nor does Billard make any reference 
to the same in his exposition. It would nevertheless seem, from Bi Hard's figure (1. c. text fig. 8) 
that the In-drotheca; point obliquely forward towards the one side, the ludrotheca; shown being indic- 
ated in oblique projection, with the aperture directed slightly forward towards the observer. Here 
again then, there is nothing which can be taken as evidence of distinction in species. 

The find here recorded extends the known distribution of this deep-sea form considerably 
towards the north, the species having hitherto been known only from the Bay of Biscay and south 
of the same. It appears to belong to the abyssal region. 



Family Campanulinidae. 

The h\-drothec£e are tubular to bell-shaped, sessile or stalked, of the radially-symmetrical type, 
more rarely with diaphragm. The hydrotheca are furnished with highly organised closing apparatus, 
falling in the shape of a roof or a pyramid over the indrawn polyp. The colonies are stolonial or 
sympodial. The polyps have a conically pointed oral part, and gastral endoderm of uniform organisation. 

The generic division of this family has given rise to much dispute, and we even find, that 

certain writers, such as Schneider (1897) and Bonne vie (1899) regard it as a single genus. The 

4 

The Ingolf-Expedilion. V. 7. 



26 



HYDROIDA II 



best exposition of the family is that given b}- Kramp, who has in two works {1911 and 1913) given 
a close description, which as regards its main features, is adhered to in the present work. Kramp 
(1913 p. 14) inclines to the view that the family should be divided into two, a primitive family, C2is- 
pidellido', where the closing apparatus is formed by the upper part of the hydrotheca wall, and a more 
highly developed family, Campaniiliindce, where the closing apparatus consists of the original roof of 
the hydrotheca. Kr amp's point of view is doubtless highly correct, but as my material is not suited 
to serve as basis for more detailed exposition, I have merely noted tlie two mentioned groups as sub- 
families, otherwise following mainly the generic division established by Kramp (191 1 p. 383). 

The gonothecge in several members of the family are of considerable interest, differing only in 
their greater dimensions from the hydrothecse — doubtless a primitive feature. This peculiarity is 
known among the genera of Stcgopoma, Ciispidella, and Lafoeina. Unfortunately, very little is known 
as to the gonophores, but we know that the family comprises the polyp-generation of a number of 
highly heterogeneous Leptomedus£e, which are distributed by systematists throughout a whole series 
of families. As, however, the polyps, save for the mentioned characters in the sub-families, exhibit 
very considerable uniformity, we can hardly, from what we know at present, consent to a further sub- 
division of the family. We have evidently here to deal with a series of biological divergencies in the 
medusa generation, particularly calculated to demonstrate the impossibility of establishing, in the pre- 
sent state of our knowledge, any common system for the two generations. The hydroid system cannot 
here be adapted to the medusa system, which evidently demands thorough investigation of the biolog- 
ical adaptation phenomena in order to give a system which can claim to be considered as fairly 
satisfactory from a phylogenetic point of view. 



Sub-family Cuspidellinae. 

Campanulinido' with closing apparatus formed bv the integrating distal part of the hydro- 
theca wall. 

Gen. Stegopoma Levinsen. 

Colony creeping or developed to an upright rhizocaulome. The hydrothecae tubular to narrow 
bell-.shaped, without diaphragm; the closing apparatus consists of two folding membranous parts of the 
distal hydrotheca wall, which shuts down in a roof-shaped lid over the aperture, between two diame- 
traliy opposite teeth. The polyps have uniform gastral endoderm. 

Stegopoma plicatile (M. Sars) Levinsen. 
1863 La/oca plica/His, M. Sars, Bema;rkninger over fire norske Hydroider, p. 31. 
1874 Calycclla plicatilis^ G. O. Sars, Bidrag til Kundskaben om Norges Hydroider, p. 95. 
1893 Slcgopoma plicatile^ Levinsen, Meduser, Ctenophorer og Hydroider, p. 37. 
1893 — caricurn^ Levinsen, — — - — P- 37- 



HYDROIDA II „_ 



Material 








a 


■Ingolf" 


St. 


28, 




— 


- 


29, 




— 


- 


32, 




— 


- 


34, 




— 


- 


35, 



:pth 420 fathoms, 


3,5° 


- 68 — 


0,2° 


- 318 - 


3,9° 


- 55 - 




— 362 — 


3,6° 


- 293 — 


-0,5° 



Colonies form upright, irregularly pinnate, polysiphonic rhizocaulomes, sometimes with creeping 
parts. Hydrothecse long, tubular, some quite free and short-stalked, others with the one side for part 
of its extent fused with the stolons; more or less curved, exceptionally with the distal part almo.st 
perpendicular to the proximal. Diaphragm lacking. Closing apparatus formed by two folding thin 
distal portions of the hydrotheca, shutting in a roof over the indrawn polyp between two strong, tooth- 
like, diametrically opposite parts of the distal portion of the liydrotheca. 

The gonothecse are situated on the branches or on the stalk. Tliey present the appearance of 
gigantic hydrothecse, with the same structure of the closing apparatus. The gonothecse are entirely 
free, short-stalked, or to a greater or lesser extent attached to the tubes. 

65°i4' N., 55°42' W.; 

65=34' N., 54°3i' W.; 

66°35' N., 56^38' W.; 

65°i7' N., 54°i7' W.; 

65°i6' N., 55°05' W.; 

- - 126, 67=19' N., i5°52' W.; 

Greenland: Davis Strait (without further details) depth 80 fathoms 

Umanak ( — — — ) 

Ritenbenk ( — — — ) on ^gu crcuulata 

Godhavn ( — — — ) 

Kara Sea, "Dijmphna" (Type specimen of Stfgoponia cariciivi.) 

This remarkable sjDecies shows an astonishing power of altering its appearance. One variant 
is described by Lev in sen (1893 p. 7,7) as a distinct species, Stegopo»m caricioii, from the fact that it 
has, at the points of the branches, only three hydrotheca-bearing stolons. This feature, however, as I 
have previously pointed out (1912 p. 11), cannot be maintained as a specific character, since it may 
occur in certain branches, while others of the same colony have four or five such tubes near the 
point; very rarely, again, we may find tlie number of hydrotheca-l^earing tubes reduced to two. It 
was also pointed out, on the same occasion, that the hydrothecse can vary, being at times entirely free, 
at others fused with the tubes. Free hydrotheca; on creeping stolons assume entirely the same appear- 
ance as in Stegopoma fastigiatiun (Alder). 

The gonothecse are mentioned several times in the literature, and have been described by 
Bonnevie (1899 p. 73) as follows: "Gonaugia large, cylindrical with circular opening at the distal 
end". Kramp, (1913 p. 16) on the other hand, describes them in the same manner as noted in the 
diagnosis, and gives excellent drawings. In the ver\' extensive material at my disposal from Trond- 
hjem Fjord, where the species is extremely frequent, I have often had occasion to observe the gono- 
thecse, whicli in all cases agreed with Kra nip's description. It might be imagined that the gono- 
thecse would exhibit sexual dimorphism; up to the present, however, I have not been able to find 
anything in support of this idea, and it unist thus be presumed that the earlier descriptions were 

based upon inadequate observation of the gonothecse. 

4* 



28 



HYDROIDA II 



Stegopo?na plicatile is an arctic species, which can ne\-ertheless penetrate into the boreal region 
(fig. VIII); its occurrence is, however, somewhat of a mystery. The species must be described as 
circumpolar, having been recorded from Davis Strait through the Norwegian Sea, the Barents Sea, 
the Kara Sea, and the Siberian Frozen Sea to the Bering Sea and the Sea of Okhotsk. Bathymetri- 
cally it is mostly found in the lower part of the littoral region. From this, then, the species should 
be noted as arctic ; as a matter of fact, however, this would not agree with the data from the northern 
Atlantic regions. There are a couple of isolated finds from the cold area, but the species has not yet 
been noted either from the east coast of Greenland or from the eastern side of Davis Strait, and 




- f ooo m. 



Fig. VIII. The occurrence of Slegopoma plicatile in the Northern Atlantic. 
In the h.itched parts the literature notes a scattered, although common occurrence. 

also appears to be entirely lacking in Iceland waters. On the other hand, we find that it is very 
common along the eastern side of Davis Strait, and — according to the records — along the west 
coast of Norway; i. e. just in those places where the warmer water layers predominate in the bathy- 
metrical area of its distribution. It may also be noted, in this connection, that the species occurs on 
the Lophohclia reefs in the Trondhjem Fjord, in quantities nnknown elsewhere. This occurrence is 
altogether mysterious in the case of a species otherwise only met with in high arctic waters; one 
would naturally expect that any extension of its distribution would follow the colder eastern shores, 
not the boreal western coasts of the continents. It is difficult at present to give any satisfactory 
explanation of this peculiarity. 



HYDROIDA II 2Q 



Gen. Cuspidella Hincks. 

Stolonial colonies, with stalkless, sessile tubular hydrothecje. The closing apparatus is formed 
by an integrating distal portion of the hydrothecse, which folds conically over the indrawn polyp; 
there is no distinct limitation between the closing apparatus and the remainder of the hydrotheca. 
Nematothecoe lacking. 

Cuspidella humilis Hincks. 
1863 Campaiiiilan'a //uiiiilis^ Hincks, M. S., Alder, Supplement to a Catalogue of the Zoophytes, p. 239. 
1866 Cuspidella humilis^ Hincks, On new British Hydroida, p. 298. 

Creeping colonies with cylindrical or slightly downward tapering hydrotheca;, passing over 
without stalk into the stolons. The hydrotheca; are set perpendicularly on the stolons, and are short, 
with a closing apparatus in which 10—12 segments can be distinguished. 

The gonothecas are set on the stolons, and are of the same shape and appearance as the hydro- 
thec£E, but much larger. The gonophores develope into free meduscC. 

Material: 

"Thor" 64°i6' N., 22°i7' W., depth 50 metres 
Reykjavik, from the bottom of a well-boat. 

This unpretending little species seems to have a fairly wide distribution, and has been met 
with from the Siberian Frozen Sea down to the Cape Verde Islands. Nevertheless, the few finds lie 
very wide apart, probably owing to the fact that the species, from its insignificant size, easily escapes 
observation. Its principal bathymetrical occurrence lies in the middle portion of the littoral region. 



Gen. Lafoeina M. Sars. 

Stolonial colonies with stalkless, sessile hydrothecse and nematothecoe. The closing apparatus 
of the hydrotheca is formed by the integrating folding part of the hydrotheca, and jDasses over without 
distinct limitation into the same; it closes conically over the indrawn polyp. The nematotheca has a 
distal laterally situated aperture. 

Hadzi points out in a letter that there are possibly two genera concealed under this definition. 
According to the drawing given by G. O. Sars, of Lafoeina tenuis (1874, tab. V, fig. 3), there seems 
to be a diaphragm occurring in this species at the junction of the hydrotheca and stolon. Levin sen 
(1893 p. 40) was not able to find any diaphragm in Lafoeina maxima, and I have likewise been unable 
to find any such here; my material, however, is of such a nature that a negative result cannot be 
considered as of decisive importance. Should it be found that certain species have a diaphragm, while 
others lack the same, it will then doubtless be most correct to divide the genus, and a further investig- 
ation of Lafoeina tenuis must then decide which of the two groups is to retain the name La/oeina. 



-Q HYDROIDA II 



Lafoeina maxima Levinsen. 
1893 Lafoeina maxima, Levinsen, Meduser, Ctenophorer og Hydroider, p. 182, tab. IV, figs. 9—12. 

The colonies form upright, robust rhizocaulomes, often combined with creeping parts, which 
spread out in plates over the underlayer. The closely set hydrothecse are cylindrical, somewhat irregul- 
arly bent, with their outer portion nearly perpendicular to the branch axis. The hydrotheca has a 
conically closing distal portion, exhibiting no distinct limitation from tlie remaining part of the same. 
Between the hydrothecse are the nematothecse, which are very numerous, and closely packed; they 
are slender, cylindrical, somewliat irregularly curved, with a distal, laterally situated oval aperture, in 
which are some few large nematocysts. 

The gonothecae are wedged in between the nematothecse and the hydrothecse; they differ neither 
in form nor in size from the hydrothecse, and their nature can thus as a rule only be determined from 
section preparations. 

Material : 

"Ingoir St. 29 65°34' N., 54°3i' W.; depth 68 fathoms 0,2° 
- 34 65°i7' N., 54°i7' W.; - 55 - 

— Holstensborg Harbour — 30 — 

Greenland: Egedesminde (without further details) 

Store Hellefiskebanke, depth 24 fathoms 

— — north of Holstensborg ( — — — ) 

Holstensborg ( — — — ) 

Godthaab, depth 60—70 fathoms 
Davis Strait — 100 — 

Iceland : Hrtitafjord, depth 45 metres. 

Lafoeina maxima is a typical arctic species, belonging to the upper half of the littoral region 
(fig. IX). The most southerly records of its occurrence are from Godthaab in Greenland, and Hruta- 
fjord in Iceland; in the Norwegian waters it has hitherto only been met with in Ramfjorden, near 
Tromso (about 69°3o' N.) 



Gen. Campanulina van Beneden. 

Colonies with sympodial growth and stalked, radially symmetrical hydrothecse. The closing 
apparatus of the hydrotheca is formed by the distal folding portion of the hydrotheca wall, and goes 
over into the same without sharj) limitation. When folded down, the closing apparatus covers the 
hydrotheca with a conical lid. The gouothecse differ in appearance from the hydrothecse. 

Kramp, in his exposition (191 1 p. 383) merely draws attention to the stalked hydrothecse of 
the genus as opposed to the sessile in Cnspidclla and Lafoeina. Further, secondary characters are, it 
would seem, here also to be found in the growth types of the colony, whether stolonial or sympodial. 



L e v i n s e n ' s 

type- 

specimeus 



HYDROIDA II 



31 



Thus the two last-named genera have, as far as we know, always stolonial colonies, whereas in 
Campanulina they are invariably synipodial. 

Campanulina turrita Hincks. 
1868 Campanulina fitrrita, Hincks, A History of the British Hydroid Zoophytes, p. 190, pi. 36, fig. 2. 
Upright synipodial colonies with monosiphonic hydrocanlus, ringed throughout. The stem 
slighth- zigzag. Stem and branches are divided into slightly pronounced internodia, bearing distally 




boom. 1000 m. 

Fig. IX. Finds of Lafoi-'ina maxima in the Northern 



Atlantic. 



an apophysis and one or two short-stalked hydrothecae; from the apophysis the next internodium 
projects. At irregular intervals, one of the hydrothecse is replaced by a branch, so that the colonies 
assume an irregularly bushy appearance. The hydrothecse are fairly large, and when closed, about 
twice as long as broad; they are practically cylindrical, with evenly curved proximal part. Diaphragm 
lacking. Closing apparatus passes over without distinct limitation into the lower portion of the hydro- 
theca wall; it closes conically over the indrawn polyp. 

The gonothecEe are set upon short, ringed stalks, projecting from the stem or branches beside 
the hydrotheca stalks. The gonotheca; are small, slender, reversed conical or cylindrical with gradu- 
ally tapering basal part; they are cut off transversely at the distal end. The gonophores develope 
(according to Hincks) into free medusse. 



-, HYDROIDA II 

6^ 



Material : 

"Ingolf, Holstensborg Harbour, on algae. 
Greenland: Smallesund near Egedesminde, on algse. 

In one of the colonies from Smallesund, a distinct renovation is discernible; unfortunately, it 
cannot be determined with certainty whether the primar_\- individual has been a hydrotheca or a gono- 
theca, but the size would seem to suggest a primary lu-drotheca. We have in this case not a hetero- 
morphotic renovate, as the renovate is a fully developed, stalked hydranth. The instance in question 
calls to mind Levinsen's description (1892) of renewal of individuals in certain Caiupaniilariidoe. 

The new find of Campanulina turrita from Greenland is highly interesting. Since Hi neks 
found the species in Ireland it has only been recorded by -Levinsen (1893 p. 181) at Egedesminde; 
from Holstensborg Harbour, the "Ingolf brought home a whole series of finely developed colonies. 



Sub-family Calycellinae.' 

Campanulmidce with closing apparatus formed by the original roof of the hydrotheca. 

Gen. Calycella (Hincks). 

Creeping colonies with tubular hydrothecse, the closing apparatus sharply marked off from the 
hydrotheca itself, and easily falling off. The closing apparatus is formed by the peripheral parts of 
the original hydrotheca roof, the central portion of which is discarded; the closing apparatus is a folding 
membrane folding conically over the indrawn polyp. The hydrotheca lacks diaphragm. 

Calycella syringa (Linne) Alder. 
1767 Sertularia syringa, Linne, Systema Naturae, ed. 12, vol. i, p. 1311. 
i860 Calicclla syringa, Alder, Descriptions of a Zoophyte . . ., p. 73. 
1868 La/oea pygmaa, Alder, pars, Hincks, A History of the British Hydroid Zoophytes, p. 205. 

Colonies creeping. Hydrotheca; tubular, often somewhat bent, with slightly outward curving 
opening margin; they are borne upon stalks, short or long, furnished with a varying number of rings. 
The closing apparatus is sharply marked off from the thicker wall of the hydrotheca, and easily falls 
off; it consists of an entire membrane, which folds down on definite lines, forming a conical roof over 
the indrawn polyp. 

The gonotheca; are attached by short, ringed stalks to the stolons. They are oval, smooth. 
Gonophores heteromedusoid. 

Material : 

"Ingolf St. 95 65°i4' N., 30=39' W.; depth 752 fathoms, 2,1° 

"Thor" 64° 16' N., 22° 1 7' W.; — 50 metres 

64°02' N., 22°33' W.; - 34 - 

' As the genus Campanulina belongs to the preceding subfamily, the present subfamily should not be called Campa- 
nulinina but better Calycelhntc. 



IIYDROIDA II 



33 



Greenland: Godliavn (without further details) 

Egedesminde ( — — — ) 

Store Hellefiskebanke off Holstensborg, depth 18—20 fathoms 
Sukkertoppen, on Bolfenia and on alga; (without further details) 
Davis Strait, depth 80 — 100 fathoms ( — — _ ) 



celand : Seydisfjord 


- 6 - 


Vadlavik 


— . 80 - 


Rodefjord 


— 95 metres 


Djupivogur 


— 8 fathoms 


Vestmano 


_ 10-15 — 


Skagi 


— 40 metres 


Hvalfjord 


46 - 


Stykkishohn 


— 30 fathoms 


Onundarfjord 


— 10 — 


Skjalfandibugt 


— 28 - 



Bredebugt 65° 17,5' N., 23°32' W., depth 7—12 fathoms 
6 miles W. of Iceland (without further details) 
The Faroe Islands: 6 miles N. by W. of Kalso, depth 60 fathoms 

Deep hole at north point of Nolso, depth 100 fathoms. 




._ tooo rr\. 



200 m. 600 m. ,_._ 

Fig. X. The distribution of Calycella syringa in the northern Atlantic. 
In the hatched retrions the literature denotes a common occurrence. 



The Ingolf-Expedition. V. 7. 



,, HYDROIDA II 

34 



It is evidently this species which is partly mentioned nnder the term Lafoea pygma-a\ according 
to Hincks (1868 p. 205) some of Alder's original drawings show a conical lid in this species, which 
at once shows that Alder's specimens, or at any rate some of them, mnst have been Calycella syringa. 
That Lafoea pygma-a is here only partly noted as synonymons with this species, is, as indicated under 
Lafoea gracillima, owing to the fact that several writers at any rate have recorded creeping colonies 
of the latter species under the same name. 

Calycella syringa appears to be a wholly cosmopolitan species, which has been met with in all 
seas. Its bathymetrical area is very extensive, ranging from about 6 metres down to nearh- 1500; it 
should nevertheless be obser\'ed that its occurrence in the abyssal region is exceptional, its chief area 
of distribution being restricted to the middle and upper parts of the littoral waters. Within the area 
investigated (fig. X) we find that it is apparently lacking 'along the greater part of the east coast 
of Greenland, where it is first met with far to the north, about 76° N. Its occurrence under high arctic 
conditions is altogether scattered, save where an intermixture of warmer water is discernible. 



Gen. Tetrapoma Levinsen. 

Stolonial colonies with tubular or narrowly bell-shaped hydrothecre without diaphragm. Closing 
apparatus formed by the original roof of the hydrotheca, and separated by a marked limitation from 
the thicker hydrotheca wall; it consists of (four) separate triangular plates, each attached in a sinus, 
between as many hydrotheca teeth. The polyps have a uniformly developed gastral endoderm, and 
lack outer ectoderm lamellae. 

In a previous work (1909 p. 165) I united this genus with Lovenella. Kramp (1911 p. 383) 
separates them again as two genera, chiefly, it would seem, on account of the number of plates in 
the lid. This feature can hardly be called important as a generic character; there is, however, another 
distinguishing feature of greater significance, which renders it necessar>- to separate the two genera. 
Hincks (1868 p. 178) especially mentions in Lovenella clausa (Loven) the presence of a diaphragm, a 
formation which does not appear to be found in Tetrapoma qiiadridentatuvi^ and which warrants generic 
distinction. Secondarily, this separation is supported by the fact that Tetrapovia has stolonial colonies, 
while those of Lovenella are synipodial' ' 

Levinsen (1913 jx 283) observes in a footnote, regarding Tetrapoii/a, "This genus must, no 
doubt, be united with Thyroscyphus''\ In this I am for several reasons unable to concur. In the first 
place, Thyroscyphiis has a distinct dia])hragm, and hydrothecte of bilateral structure; in the second, 
the structure of the pohp also is entirely different. Tliyroscyphtts, with its ectoderm lamellfe and inci- 
pient blind sack formation, as also the differentiated gastral endoderm, exhibits closer relationship with 
Scrliilaruda-, and should probably far rather be considered as a primitive genus of this family. 



Tetrapoma quadridentatutn (Hincks) Levinsen. 
1874 Callycella quadridenlata, Hincks, On deep-water Hydroida from Iceland, p. 149, pi. 8, figs. 17 — 20. 
1893 Tetrapoma quadridentatum^ Levinsen, IMeduser, Ctenophorer og Hydroider, p. 180. 

' Coiiip. also Lovenella corriigaia Tlionicly i lirocli iyi4 p. .^2). 



HYDROIDA II 25 



Creeping colonies witli tubular Indrotheca;. The hydrotheca stalk is irregularly, but distinctly 
ringed or spirally coiled. The hydrothecie pass over evenly into the stalk, they are somewhat 
expanded at the base, then tapering slighth- upwards, to expand again a little towards the open- 
ing margin, which curves somewhat outwards. The opening margin itself has four low, but distinctly 
discernible teeth, and has four triangular opercular plates fastened between them. 

The gonothecse are unknown. 

Material : 

Greenland: Egedesniinde, depth 30-50 fathoms. 

Scattered specimens of this high-arctic species have been found at West Greenland, Spitzbergen, 
in the Murman Sea, the Barents Sea, the White Sea, the Siberian frozen Sea and the Sea of Okhotsk, 
and must thus doubtless be referred to the circumpolar species. It belongs to the middle parts of the 
littoral region. 



Family series Haleciina nov. 
Family Haieciidae. 

The hvdrothecse are radially symmetrical and verv small, at times practicall} altogether dis- 
appearing; thev have as a rule a basal cavity, often marked off from the hydrotheca itself by a dia- 
phragm. The hvdranths are large, and cannot be drawn quite into the hydrotheca\ The\- have a 
conical proboscis, and their gastral endoderm falls into two divisions, answering to the fore-stomach 
and stomach of the polyp, which as a rule are separated by a limit indicated by a more or less marked 
ring furrow round the body of the polyp. The basal part, the stomach, forms the digestive portion. 
The polyps are radially symmetrical in structure. The colonies are stolonial or sympodial, with .simple 
or derived growth of the tips. 

Gen. Halecium Oken. 

Creeping stolonial, or upright sympodial colonies with small radially symmetrical hydrothecse 
with basal cavity. The diaphragm can be present or lacking. Nematothecte and nematophores lacking. 
The gonophores are developed in gonothecse. 

The Halecium colon\-, in species with polysiphonic stem, often presents a peculiar appearance, 
differing greatly from that of other hydroid colonies, as the polysiphonic main stem, which is gener- 
alh- very strongly developed, most frequently presents the same impression as an altogether irregularly 
branched rhizocaulome, while the outer parts of the branches almost always exhibit regular ramifica- 
tion. Halfciitm iiiii/ufKiii Broch especially, seems in some respects to take up a remarkable and 
exceptional position; according to Kra nip's observations (1913 p. 5) it can at times exhibit large colon- 
ies of composite structure with rhizocaulome-like polysiphonic main stem and main branches, while 
otherwise, the species normalh' presents small, monosiphonic colonies proceeding from a network of 

5' 



36 



HYDROIDA II 



creeping stolons. This thus confirms, as Kramp points out, the doubts which have been expressed 
by certain previous writers as to the fundamental importance of the structure of the colony for hydroid 
systematics, and partly effaces the limit between creeping species and species with upright, composite 
colonies. 

The genus Halecium is characterised by the liveh- renovation of its hydranths. This should, 
it would seem, be explained as due partly to the lack of special defensive individuals, partly to the 
minimal size of the hydrothecse, and finally also to the large dimensions of the polyps, which probably 
render them particularly attractive to creatures preying upon hydroids generally. The marked reno- 
vation activity often leads to the formation of whole piles of hydrothecse, or apparently small branches, 
for which Schydlowski (1901) has introduced the term "pseudohydrocauli". 

Not infrequently also, heteromorphotic renovates may be observed; I have previously (1909 p. 
151) noticed that the formation of gonothecte as heterorenovates is characteristic of the male in Hale- 
cium ornatum Nutting. Heteromorphotic renovates of a more accidental nature will be noted later 
on in several species; these are of great interest, since renovates of this kind have, according to 
Had/, i (1915) only been met with in nature among lialcciiiin and Sytitheciidir. The question has, 
however, been too little studied as yet to permit of our drawing further conclusions from this, but 
the point should be kept in mind, until it has been fully cleared up. 

Halecium halecinum (Linne) Oken. 
1758 Sertularia halrcina, Linne, S>stema Naturae, Ed. 10, p. 809. 
1815 Halccmm haleci)ium, Oken, Lehrbuch der Naturgeschichte, vol. i, p. 91. 

Stiffly built, as a rule doubly pinnate colonies with polysiphonic main stem. The branches 
are as a rule pinuatel)- raTuified in the same plane as the main stem, or the colonies may, more rarely, 
assume an irregular bushy shape. The minor branches are divided up into regular internodia, the 
lengtii of which is about twice the distal breadth. The primary hydrothecse are low, often almost 
like a mere opening in the branch apophysis at the distal end of the internodium. The secondary 
hydrothecse are small, with a large basal cavity, generally somewhat asymmetrically developed, and 
having the basal part of its adcauline wall highly concave. The hydrothecae are somewhat broader 
at the ajjcrture than at the well-developed, fairly strong diaphragm; the opening margin is not 
curved outward. 

The gonothecse are large, and proceed from the apophysis at the base of the primary hydro- 
thecse. The males are narrowly c\lindrical to elongated oval, tapering below, distally cut off trans- 
versely, or more often broadly rounded. The female gonothecse have a distal laterally placed aperture 
with a pair of Indranths; the aperture is furnished with a short cylindrical neck, and situate normally 
at the distal end of the hydrothecse; more rarely, the distal part of the gonotheca may be domed 
somewhat forward, so that the opening is a little below the point. The gonotheca is slender, almost 
entirely straight or slightly convex on the side opposite the pair of hjdranths, and tapering evenly 
downwards. 



HYDROIDA II ,y 



Material : 

"Ingolf" St. 7, 63° 13' N., i5°4i' W., depth 600 fatlioms, 4,5° 
- - 9, 64°i8' N., 27^00' W., - 295 - 5,8° 

- 54, 63'>o8' N., 15-40' VV, - 691 - 3,9° 

"Thor" 63-30' N., 20°i4' W., — 80 metres — [labelled Halecium halecinum^ H. 

Beaiiii and //. lubrosu7n\ 
Greenland: Cape Tobin, depth 57 fathoms (East Greenland Expedition). 
Iceland : Vadlavik (depth not stated) 

Vestmano, depth 30—40 fathoms |labelled Halcciuin Jinlrciumn and //. Beanii] 
10 miles W. of Akranes (depth not stated) [labelled Htilt-ci/i./ii Braiiii]. 
Between Iceland and The Faroe Islands, depth 192 fathoms (without further details) 
The Faroe Islands : 6 miles N. by W. of Kalso, depth 60 fathoms 
Stokken 2 miles in S.22E., — 55 — 
Deep hole at north point of Nolso, depth 100 fathom.s. 
Glyversnses near Thorshavn, on red algae. 
Boronces 13 miles in N.75W., depth 30 fathoms. 

Halcciuin halcciuiiiii is generally of somewhat coarser build than Halecium Bcaiiii^ but a good 
deal finer than Halecium scutiiiii\ it is often extremely difficult to distinguish these species one from 
another, especially when the colonies assume an altogether irregular form, whicli 
the males in particular are inclined to do. The female gonotheca; in Halecium 
halecinuiii will, in their normal shape, with the quite terminal lateral opening, 
hardly be confused with normal individuals of the other species, but when, as not 
infrequently occnrs, the distal portion of the gonotheca is domed forward, so that 
the aperture is found somewhat below the point on one side of the gonotheca, 
the identity is bv no means eas\' to determine. True, Halcciuin scutum is in 
most mstances of far coarser build than the two others, but the variation in dim- 
ensions is within each of the three too great to permit the fixing of proper size 

Fig. XI. Hatecium hale- 

limits; they would be found to overlap considerably. A useful general character ,,>,„„,. internode with 

for Halecium halecinum is the asvmmetrical development of the basal ca\itv in liydrothecse. From the 

^ ■ Faroe Islands at north 

the secondary h\drotheca (fig. XI); the basal part of the adcanline wall is more point of Nolso. (x 60). 
strongly developed, and highly curved, so that the hydrotheca axis thus diverges widely from the 
branch. On the other hand it must be remarked that the hydrotheca aperture is perpendicular to the 
longitudinal axis, a feature whereby the species is distinguished from Halecium Beanii. 

Halecium lialeciiiuin has an extremely wide area of distribution, and is very common right up 
in the Mediterranean; it has also been recorded from waters south of the Equator. In the northern waters, 
the species appears as a boreal character form, with warmer tendency (I'ig. XII) and is mostly met 
with in the middle part of the littoral region; at times, however, it may penetrate right down into 
the abyssal, as at the "Ingolf" St. 54, where it was taken in a depth of over 1300 metres. In purely 
arctic waters, it is very rare, and records of its occurrence there must be treated as doubtful, as it 




38 



HYDROIDA II 



has evidently on several occasions been confused with Halccmm scufuni. The same applies in part 
to certain of the records from southern waters, where the species has undoubtedl)- often been mixed 
up with Haleciuvi Beanii. 



Halecium Beanii Johnston. 
1847 Halecium Beanii, Johnston, A history of the British Zoophytes p. 59, pi. 9, figs, i -2. 

Upright densely built colonies with polysiphonic, fairly robust main stem, and monosiphonic, 
pinnately ramified outer branches; the ramification of the colony presents as a rule a main plane. The 




200 m. . _ . _ 600 m. tooom. ._ 2000m 

Fig. XII. The distribution of Hakanm halecimnn in the northern .\tlantic. 
In the hatched regions the hterature denotes a couimon occurrence. 

minor branches are divided into slender regular internodia; the distally situate, hydrotheca-bearing 
apophyse is almost of the same breadth as the branch itself, and sharply defined; the length of the 
internodium is about 2 — 2.5 times the distal breadth (including apophyse). The hydrothecte small, 
bounded on the lower side by a slight diaphragm. The primary hydrothecse are hardly more than 
an aperture in the apophyse, and the hydranth is evidently very soon renewed; the basal chamber of 
the secondar\- ludrotheca is symmetrical, with a distinctly marked basal expansion; above this the 
hydrotheca stalk is narrowest, its breadth increasing slightly from there until it passes over into the 
somewhat obliquely set hydrotheca; the latter is a little broader at the aperture than at the diaphragm; 
opening margin not outward curved. 

Gonothecee of medium size, proceeding from the apophyse of the ])rimar\- h>drothecse. The 



HYDROIDA II 



39 



males are very elongated oval, the females elongated oval to sausage-shaped, highly curved, with a 
short c\'lindrical neck in the middle or on the basal half of the gonotlieca, and on the concave side 
of the same. Opening margin level; in the opening itself a pair of hydranths. 

Material: 

"Thor" 63°3o' N., 2o°i4' W., depth 80 metres. 

The Faroe Islands: Boronaes 13 miles in N75W., depth 30 fathoms. 

On a previous occassion (1913 p. 13) I stated that Ifalrci/ii// Bnii/ii should be regarded as a 
variant of Halcciiini haleci)iniii\ further investigations have, however, shown that this is not correct, 
even though the two species, more particularly 
in a sterile state, may often enough be difficult 
to distinguish. Fertile female colonies are not 
easily confused, the form of the gonotlieca; being 
typically different; in comparison with the follow- 
ing species it should be noted that the aperture 
in IIalccin))i Bcanii lies roughh' in a line with 
the basal and distal end of the gonotheca, and 
that the neck axis closely approaches, if not entirely 
coinciding with, this line. (Fig. XIII). The bran- 
ches are, in Haltxnun Beanii, often slenderer than 
in Halecium halecinum and Haleciuni scicfiiiii, and 
the apophyse is somewhat more marked; in addit- 
ion, the basal chamber of the secondary hydro- 
theca is symmetrically developed, and not asym- 
metrical as in Halecuun halrchntm; finally also, 
the oblique position of the hydrotheca aperture as towards the axis serves to distinguish Halecium 
Beanii from the two related species mentioned. 

The geographical data for Ffah-ciiini Beanii are extremely unreliable as regards the northern 
waters; the species is, as I have frequently been able to perceive, often confused with //rt/fc/w/// jcz^^ww 
in arctic, with Halecium halcciiinin in boreal areas. In all probability, it is a heat-loving form, which 
exceptionally penetrates into the northern waters. 





Fig. XIII. Halecium Beanii. 
Inteniode with hydrothecse. b. Gonotheca ?. From the 
Faroe Islands, Boronais 13 miles in N.ysW. X 6o- 



Halecium scutum Clark. 

1876 Halecium scultiut, Clark, Report on the Hydroids Alaska and the Aleutian Islands, p. 2io, 

pi. 10, fig.s. 13—14. 

Robust colonies with polysiphonic main stem. The outermost small branches exhibit an almost 
regular pinnate ramification in the same principal plane as that in which the branching of the colony 
falls; more rarely, the colonies may be quite irregularly bushy. The minor branches are divided up 
into internodia, the length of which is about twice the distal breadth (apophyse included). The primary 



.„ HYDROIDA II 

40 



hydrothecse are low, often hardly more than an opening in the apopliyse, which is distally placed, and 
distinctly marked. The secondary hydrothecse are likewise small, with a fairly large basal chamber, 
which is almost always symmetrically developed. The hydrotheca; have a thin, but well-developed 
diaphragm; they expand towards the aperture, but have no outward curving margin. 

The gonothecffi are small, and attached to the apophyse at the base of the primary hydrothec^ 
The males are cylindrical to elongated oval, tapering downwards, broadly rounded distally, or cut off 
transversely. The female gonothecse have a laterally placed opening with a pair of hydranths; the 
opening margin has on its inner (adthecal) side a short, broadly lingueform protuberance. The gouo- 
theca openings are situated between the middle and the distal end of the gonotheca, rarely quite 
distally. The gonotheca is often somewhat irregularly bent. 

Material : 

"Ingolf St. 31, 66°35' N., 55°54' W., depth 88 fathoms 1,6° 

- - 34, 65°i7' N., 54°i7' W., - 55 - 

Greenland: Sukkertoppen (without further details) 

Davis Strait, depth 100 fathoms (without further details) [labelled Ilaleciiivi Beanii\ 
Iceland: Vadlavik, (depth not stated) [labelled Halccium Bcani'i] 

Between Iceland and The Faroe Islands: 63°i5' N., 9°35' W., depth 270 fathoms [labelled Hale- 

cium Beanii"\ 
The Faroe Islands: Deep hole at north point of Nolso, depth 100 fathoms 

6i°4o' N., 7°4o' W., depth 135 fathoms 
Kara Sea: "Dijmphna" [labelled Halecmin Beanii]. 

It is not without a certain doubt that we can admit Halechim scntmii as a distinct species 
and not as an arctic form of Halecmin halecimim. From a geographical point of view, as also with 
regard to most of the variational features, it stands in almost exactly the same relation to the last- 
named species as the arctic forms of several other more or less cosmopolitan hydroids. And it is also 
Halecium scutum which has formerly (Broch 1909 p. 144) been noted as forma gigantea of Halecium 
halecinuvi. 

A comparison of the two species reveals various points of resemblance. Bonnevie's state- 
ment (1899 p. 57) "ramification in all planes" as a characteristic feature cannot be admitted; it applies 
as a matter of fact far more to the exceptions, the great majority of the colonies exhibiting a decided 
main plane in which the ramification takes place. On the other hand, the short and broad internodia 
(fig. XIV a) are typical, and differ not a little from Halccniiii Bcanii\ with which the species has espe- 
cially been confused. The secondary hydrothecse differ normally from Halecium halecimtni in having 
a symmetrical and proportionately lower basal cavity, and from Halecium Beanii in having the plane 
of the aperture perpendicular to the longitudinal axis. — The frequent confusion of Halecium scutum 
with Halectu?n Beanii is due to the great variability of the female gonothecse (figs. XIV b—h) which 
not infrequently (<?—/) resemble strongly those of the latter species. We should, however, note that 
in Halecium scutum the aperture and its short neck are as a rule obliquely ]3iaced, diverging widely 
from the line between the stalk of the gonotheca and its top; in addition, the gonotheca has an 



HYDROIDA II 



41 



adthecal lingueform protuberance whicli is lacking in Ifalciiuiii Bcanii. The extreme variants in the 
other direction, ((^ and c\ h) are markedly suggestive of broadly built gonothecje in Halecium haleci- 
num, so that fertile colonies likewise may here often be confused. The illustration c shows a gono- 
theca which has arisen as a heteromorphotic renovate. 









Fig. XIV a — /;. Hahxmin scutum, 
a. Interiiodiuni and secondary hydrotheca. Davis Strait 

100 fathoms (X 60). 

b—e. Gonothecse from a colony (9) in Kara sea (> 30). 

f—h. Gonothecse from a colony (9) in Davis Strait 

depth 100 fathoms (X 30). 

Every gonotheca contains fully developed 

planula larvae. 

The material includes several specim- 
ens of Halecium scutuvi which had previ- 
ously been determined as Halcciioii Bcauii\ 
this shows, that extreme caution should be 
observed in dealing with records in literature 
of the last-named species, the occurrence of 
which under arctic conditions is, as above -^ ^ 

mentioned, doubtful. Halecium scutitiii, on the other hand, is an arctic character form, with cncuni- 
polar distribution. In the waters investigated (fig. XV) it is found in the lower part of the littoral 
region, but quite exceptionally, as at the Faroe Islands, does it penetrate to any considerable extent 
into the warmer boreal waters. 

Halecium curvicaule v. Lorenz. 
1886 Halecium curvicaule, v. Lorenz, Polypomedusen von Jan Mayen, p. 25, pi. 2, figs. 1—2. 

Colonies creeping or upright, with irregular, more rarely almost dichotomic ramification, mono- 

siphonic hydrocaulus. Hydrotheca: terminal: the next hydrotheca stalk or branch internodium proceeds 

6 

The Ingolf-Expedition. V. 7. 



42 



HYDROIDA II 



from an almost spherical apophyse situate close under the terminal hydrotheca. The hydrotheca itself 
is low, somewhat broader at the aperture than at the faint diaphragm, more rarely with margin slightly 
bent over. Secondary hydrothecse occur in smaller numbers. The hydrotheca stalks are as a rule 
fairly long, as a rule with a couple of rings below. 

The gonothecse proceed from the hydrotheca stalks close under the polyp, and are attached 
by a short, often almost quite rudimentary stalk, or are exceptionally formed as heterorenovates in the 
hydrothecse. The males are elongated oval or narrowly egg-shaped, attached to the colony by their 
narrower end. The female gonothecae are practically pear-shaped, laterally compressed, and with a 
pair of hydranths in the distal, asymmetrically placed opening ; on the side opposite this aperture, the 




200 m. 



. boom. 



2 ooo m 



Kig. XV. Finds of Hakcium scutum in the Northern Atlantic, 
o I^ocalities of Halecium Beanii after Kramp (1914), referring to Halechim scutum. 

gonotheca has 2—9 transverse furrows, more or less pronounced, at times almost imperceptible; they 
never reach right round the gonotheca. 

"Ingolf St. 29, 65°34' N., 54°3i' W., depth 68 fathoms, 0,2° 
Greenland: Egedesminde (without further details) 
Iceland: Bakkefjord, depth 10 fathoms 
Hvalfjord, — 46 metres. 

A detailed description of Halcciuvi curvicmilc has been given by Dons (1912 p. 61) who shows, 
that Halecmvi mirabilc Schydlowsky and //^/Armw/ r^/^-wj J ad er holm are synonyms to this species. 



HYDROIDA II 



43 



Examination of a large amount of material leaves no doubt as to the correctness of this. The species 
is enormously multifarious in its power of variation, and has a remarkable capability of changing its 
appearance; an examination of the branches, however, will always reveal the characteristic, almost 
spherical apophyse typical of the species, and the distinguishing characters established are seen to be 
founded on growth stages. 

Dons does not appear to have noticed that his figure D. 5 shows how the male gonotheca 
can be formed in hydrotheca as a heteromorphotic renovate. This is particularly interesting in the 
case of the present species, since other heteromorphotic renovates likewise appear in the same in nature, 
as tendril-like stolon formations in place of hydranths. Dons mentions such renovates, with illustra- 




300 m. 600 m. tooo m. 

Fig. XVI. Ivocalities of Halechim curvicaiih- in the Northern Atlantic. 



2000 m. 



tions, and points out that these very features have served as the basis on which the species Haleciiini 
tuirabtle was established. The species is thus characterised b\- a less lively h\dranth renewal, but has 
on the other hand a more marked tendency to form heteromorphotic renovates than most other forms 
of Haleciuin. 

Haleciitm cjirvicanlc is a markedly high-arctic species, belonging to the littoral region. Only 
quite exceptionally does it penetrate into boreal waters (fig. XVI) as for instance at Iceland. Off the 
coast of Norway it has not yet been met with south of Bjarkoy. 



Haleclum muricatum (Ellis and Solander) Johnston. 
1786 Sertularia vmricata, Ellis and Solander, The natural history of many curious an uncommon Zoo- 
phytes, p. 59, pi. 7, figs. 3—4. 

1847 HaleciuDi luiiricahiiii, Johnston, A histor\- of the British Zoophytes, p. 60, pi. 9. figs. 3—4 

6* 



HYDROIDA II 
44 



Upright colonies with polysiphonic, irregularly ramified main stem, and regular singly or 
doubly pinnate branches; the outer, minor branchlets regularly alternating. The hydrothecse small, with 
expanded margin, especially on the adcauline side ; the basal cavity is large, somewhat asymmetrically 
developed, with a markedly convex adcauline wall and a straight or slightly concave abcauline wall, 
inserted asymmetrically on a laterally placed apophyse at the distal end of the internodium. The 
branches are divided into internodia, which often exhibit one or two basal constrictions. 

The gonotheca; proceed from the tubes of the stem. They are large, somewhat flattened, and 
furnished with .spiny longitudinal ribs on the flat .side. 

Material: 

"Ingolf St. 29 65°34' N., 54°3i' W., depth 68 fathoms 0,2° 

- - 34 65°i7' N., 54°i7' W., - 55 - 

- - 84 62°58' N., 25°24' W., — 633 - 4,8° 
"Thor" 65°52' N., 23°58' W., — 62 metres 

- 64°i6' N., 22°i7' W., - 50 ~ 

— 64°i6' N., ii°i5' W., — 378 — 
Greenland: Egedesminde (without further details) 

Store Hellefiskebanke ( — — — ) 

Store Hellefiskebanke depth 24 fathoms 

Davis Strait ( — — — ) — 100 — 

Ingmikertok, Angmagsalikfjord (East Greenland Expedition) 
Iceland: Mouth of Hornafjord (depth not stated) 
Rodefjord, depth 80 fathoms 
Djupivogr — 8 — 
Vestmano — 10 — 15 — 
10 miles W. of Akranes (depth not stated) 
Stykkisholm, depth 30 fathoms 

Bredebugt 65°i7' N., 23°32' W., depth 7—12 fathoms 
Adelvik (dcptli not stated). 
The Faroe Islands: 7 miles N. by E. of Myggenses point, depth 57 fathoms 
6 miles N. by W. of Store Kalso, — 60 — 

Deep hole at north point of Nolso — 100 — 

5 miles SSE. of Bispen — 50 — 

Forma abyssalis: 

"Ingolf St. 125, 68°o8' N., i6°02' W.; depth 729 fathoms, —0,8° 

rialecium niuricatum, with its as>mmetrically developed hydrotheca stalks or basal cavities 
and its slenderer form, stands out distinctly from the remainder of the northern Haleciuin species, and 
is not easily confused. It is as a rule finely built, but may occur in large colonies with highly rami- 
fied polysiphonic main stem; the ramification then mostly proceeds in a main plane, but can also be 
altogether irregular, so that the colonies assume a quite bushy appearance. The margin of the hydro- 



HYDROIDA II 



45 




theca can vary with regard to curvature, and may in extreme cases somewhat resemble Halecium 
labrositiii\ in Halechan Diuricafiiiii however, we alwa_\s find tliat the adcanHne margin of tlie hydro- 
theca is more markedly curved, the abcauline less so. 

Normally, the length of the internodium is about three times its distal breadth (including the 
apophyse); we have, however, from the "Ingolf St. 125, a colony which, from its extremely long inter- 
nodia, must be regarded as a deep-sea variant (fig. XVII b\ forma abyssalis nov. It is not unusual 
among hydroids to find that the colonies from greater depths exhibit an extension of tlie single branch 
parts; in this case, however, the tendency is pushed to an extreme, and at a first glance, the colony 
presents an altogether alien appearance. It is probably due to the fact that the species here occurs 
in the cold area, at the considerable depth of 729 fathoms. The colonies are very slender, about 10 cm 
high, with polysiphonic stems. The 
internodia of the minor branches are 
3—4 mm long, about five times the 
distal breadth inch apophyse. The 
apophyse itself is very distinctly mar- 
ked and bears a slender hydrotheca. 
The hydrotheca has close under the 
diaphragm the typical adcauline thick- 
ening of the wall, the "pseudodia- 
phragm" wliich as a rule is also found 
in the typical form. The hydrothecse 
exhibit the form t\pical for the spe- 
cies; the secondary hydrotheca; are 
comijaratively short-stalked, but other- 
wise of the same shape as the pri- 
mary. The colonies are sterile. From "f forma abyssalis from -ingolf 
the features mentioned it follows that ■ • a- 

the colonies cannot be taken as representatives of a distinct species; they should, however, be distin- 
guished as the type of a particular forma abyssalis of the original species. 

Halecium )nuricatii)ii is a circumpolar arctic species, able to penetrate into the boreal region 
and out to the limits between this and warmer layers (fig. XVIII). Its principal occurrence is restricted 
to the upper part of the littoral region, but it may, as seen from the foregoing, penetrate far down 
into the abyssal. It was met with already by the Norwegian North-Atlantic Expedition at a depth of 
1350 metres. 

Halecium labrosum Alder. 
1859 Halecium labrosum. Alder. Descriptions of three new species of Sertularian Zoophytes, p. 351, pi. 13. 

Robust, upright, and irregularh- branched colonies with polysiplionic main stem. The hydrothecse 
are short, symmetrical, with markedly recurvate aperture margin. The basal cavity is very large, and 
bounded above by the base of tlie Indranth; the diaphragm rudimentary or entirely lacking. The 



Fig. XVII <7— *. 
HaUciiim nnin'catum. 
a_ Internodium and hydrothecse 
from a tj-pical colony from Store 
Hellefiskebanke, depth 32 fath. 
b. Internodium with hydrothecse 




46 



HYDROIDA II 



branches are divided into fairly short internodia, having a hydrotheca on the distal apophyse; the latter 
is often, though not always, separated from the basal cavity of the hydrotheca by a joint. 

The gonothecse are very large, and proceed from the tubes of the stem and branches, or from 
the apophyse. They are irregularly oval, flattened, without spines or ribs, the females are much larger 
than the males, often more flattened in proportion, but otherwise of the same shape. 

Material : 

"Ingolf St. 33 67°57' N., 55°3o' W., depth 35 fathoms 0,8° 
Greenland: Egede.sminde (without further details) 

Store Hellefiskebanke ( — — — ) 

Davis Strait, depth 100 fathoms ( — , — — ) 
_ _ 67°34' N., 55°2o' W., (depth not stated) 
Iceland: Vadlavig, depth 46 fathoms 
Vestmano, — 28 — 

Halecm7ii Inbrosum is an arctic .species capable of penetrating into the boreal areas (fig. XIX). 
In strictly arctic waters it is of very robust build, perhaps the coarsest of all arctic Halecium species, 
and can hardly be confused with others. In warmer parts, it assumes a somewhat finer structure, but 
should even here be reckoned among the robust forms. Bathymetrically, the species belongs to the 
uj)per part of the littoral region, and has very rarely been observed below this. The few records of 
its occurrence in the Mediterranean and Atlantic south of the boreal region demand renewed investi- 
gation, as much would seem to suggest that confusion has taken place. 

Halecium tenellum Hincks. 
1861 Halecium (enclluni., Hincks, A catalogue of the Zoophytes of South Devon, p. 252, pi. 6, figs. 1—4. 

Pigii Halecium textum, Kramp, Report on the Hydroids the Danmark Expedition, p. 368, pi. 

XXI, figs. 5-6. 

Colonies upright, with mouosiphonic hydrocanlns, and typical, somewhat irregularly sympodial 
growth. The branches — the new hydrotheca stalks — proceed from close beneath the basis of the 
terminal primary hydrotheca, not infrequently in pairs, so that dichotomic ramification takes place; 
more rarely several branches from the same point. Pseudohydrocauli are of minor importance in the 
colonies, the renewal of hydrothecie is not particularly active. The hydrothecse are of medium size, 
broadening upward from the slight diaphragm and terminating in an often recurvate opening margin. 
The stalk of the secondary hydrotheca; is ringed, the branches are often ringed throughout their 
entire length, and exhibit at any rate distinct rings above their origin. 

The gonothecse proceed from the base of the primary hydrothecse, or more rarely, they may 
be formed as heteromorphotic renovates in the hydrothecse themselves. The gonotheca is somewhat 
flattened; viewed from the broad side they are elongated oval, with the distal part cut off transversely 
or broadly rounded; seen laterally, they are more egg-shaped, with a pointed distal part. They lack 
hydranth pairs. 

Material: 

"Ingolf St. 87 65°02,3' N., 23=56,2' W., depth no fathoms 



HYDROIDA II 



47 




SOO rn. ^ 600 m. -.._». ^._iooom. 2 ooo m 

Fig. XVIII. The distribution of Halecmm muricatum (forma abyssalis J- I in the Northern Atlantic. 
In the hatched regions the Hterature notes a common, although scattered occurrence. 




SCO m. 



Fig. XIX. The occurrence of Halecitim labrosum in the Northern Atlantic. 
In the hatched parts the occurrence according to hterature is scattered, no accurate details as to localities are given. 



48 



HYDROIDA II 



Greenland: Sukkertoppen, on Boltcnia (without further details). 
Iceland: Brunnes, depth. 4 fathoms 
Seydisfjord — 6 — 
Hvalfjord — 46 metres 
Stykkisholm — 30 fathoms. 
The Faroe Islands: 6 miles N. by W. of Store Kalso, depth 60 fathoms 
Deep hole at north point of Nolso — 100 — 
Glyversnses near Thorshavn, on red algie. 

There may be some possibility that the colony here 
shown (fig. XX) from the "Ingolf" St. 87 does not altogether 
agree with Halcciuni tenelluDi. On comparing with the des- 
criptions given by Hincks (1868 p. 226, pi. 45, fig. 1 c), Rit- 
chie (1907 p. 525), and Jaderholm (1909 p. 14) the gono- 
thecte do not agree with those shown. Hincks describes 
them as follows: "the capsules vary in form, being broadly 
ovate, or slender and somewhat pointed above; they contain 
a single, large gonophore". His figure shows us a slenderly 
oval or more pear-shaped gonotheca broadly rounded at the 
distal end. Ritchie's description is as follows: "The gon- 
angia are ovate, broad in the proximal region, obtusely pointed 
in the distal. They are supported on short stalks, which arise 
from the sides of the hydrotheca, and always from the lowest 
segment in any hydrotheca tier". Jaderholm writes: "Go- 
notheken eirund, unter den Hydrotheken ausgehend und (nach 
Thornely) auch von der Hydrorhiza und aus der Hydro- 
thekenmiindung. Distale Zahne fehlen". From the statements 
here quoted, it is not easy to gain a clear impression of the 
gonangia, and none of them will altogether cover the present fertile colonies, of which there are 
not a few in my material, and which agree with the specimen shown. 

The gonothecse are here set on short stalks, close under the primary hydrothecte, or may 
exceptionally arise from the interior of the same; this agrees with the statements given above, 
as also with a later observation by Ritchie (1911 p. 30) where however, nothing new is stated as to 
their shape. The gonotheca contain.s, as Hincks points out, a single large gonophore, but the state 
of preservation of the material did not permit further investigation of this. On the other hand, the 
.shape of the gonotheca agrees but ill with Hincks's drawing, and forms rather a cross between 
the description given by Ritchie and that of Jaderholm, not improbably because the gonothecce 
are somewhat flattened. In lateral view, they are egg-shaped, with a broad basal part, and pointed 
distal end; viewed from the flat, on the other hand, they are more elongated oval, more or less trans- 
versely cut off at the distal end. On comparing this with the passage from Hincks's description 
quoted above, we find that his expression "broadly ovate, or somewhat pointed above" agrees after 




Fig. XX. Halfcium tenrlhim. 

Q from "Ingolf St. 87. 

By * a gonotheca formed as heterorenovate. 

(X 20). 



IIYDROIDA II 



49 



all, as long as we bear in mind that the two statements refer to the gonotheca as viewed in the one 
case from the flat, in the other from the side. Conseqnently, all things considered, I regard the col- 
onies in question as representatives of Haleciuin tenellnin. 

Jaderholm (1909 p. 55) notes Halecinm Schneider i (Bonnevie) (1898 p. 10) as synonymons with 
Halecium toielliiui; this, however, reqnires further justification. The shape of the colony, and the 
lively formation of pseudohydrocauli in Haleciuin Sc/iiifideri, agree rather with Halecium nmmtum, 
but the identity of the species is altogether doubtful, from the data we possess. Should the female 
gonotheca; prove to correspond with Schneider's Haleciuin nainiin (1898 p. 481) then we have here 
a species entirely distinct from Halecium tenelluin and Haleciuin ininuluin. Similarly, it may be doubtful 




6con. tooo m. 

Fig. XXI. Finds of Halecium tenel/um in the Northern Atlantic. 



whether the species noted by me (1913 p. 17I as Haleciuin tenelluin, from the Adriatic, really belongs 
here; the method of growth of the colony, and its dimensions, differ to such a degree from what is 
found in northern specimens of Halecium leitellum, that we must await demonstration of the gonotheca; 
in the Adriatic form before we can determine with certainty whether it belongs to this species. 

The colonies agree on the other hand very well with the Halecium textuin described by 
Kramp (1911 p. 368); the marked curvature of the hydrotheca margin in this species is not more 
pronounced than is frequent!}- met with in Halecium tenelluin \ here, however, we must also await the 
finding of gonangia. It would also seem likely, as Kramp (1914 p. 1003) points out, that the Hale- 
ciuvi criiiis described by Stechow (1913 p. 79) belongs under Halecium tettellum\ Stechow's inter- 
pretation of the manner of ramification in the colon}- is based upon an entirely erroneous appreciation 

The Ingolt'-Expeditioii. V. 7. 7 



i,Q HYDROIDA II 



of the actual conditions; a point which has likewise been demonstrated by Kramp. Stechow's 
drawings in the mentioned work are sadly schematic, and thus afford but poor support. 

Halecium tenelhcm belongs to the littoral region, and appears to occur but rarely deeper down 
in northern waters. From records in the literature, the species is altogether cosmopolitan, penetrating 
far into the Arctic waters, albeit it must here evidently have been frequently confused with the related 
Halecium minuhivi. Despite the fact that it is cosmopolitan, its occurrence in the boreal waters (fig. 
XXI) is remarkably scattered, and apparently irregular. It is probably considerably more common than 
appears from the chart, but occurs often in insignificant little colonies which may easily escape notice. 

Halecium minutum Broch. 
1903 Halecium minutum, Broch, Die von . . . "Michael Sars" . . . gesammelten Hydroiden, p. 4, Taf. I, 

figs. 1—4. 

Colonies upright, generally with small, monosiphonic h}'drocaulus, with regular, zigzag shaped 
sympodial growth; these small colonies arise as a rule from creeping stolons, but at times the stolons 
may collect together into well developed, branched and polysiphonic rhizocaulome-like formations, 
from which small branches with s\iupodial ramification proceed. New branchlets arise from under the 
base of the primary hydrothecis:, normally only one branch at the hydrotheca. The renewal of the 
hydrothecje is lively, and gives rise to psendohydrocauli, which may more rarely serve as the base 
for secondary sympodial formations. The hydrothecse are fairly large, expanding considerably upwards 
from the slightly developed diaphragm, and have as a rule a highly curved margin ; the stalks of the 
secondary hydrothecse are ringed; the branches have distinct rings under the uppermost hydrothecse, 
rarely elsewhere. 

The gonothecfe arise from the creeping stolons or from the tubes of the polysiphonic parts of 
the colony. The females are very large, up to 3 mm. long, broad oval to round, and may not infre- 
quently even be broader than long; they are highly flattened, with spines along the edge, especially in 
the distal part. The male gonothecae are smaller, elliptical, and smooth; they may also proceed from 
beneath the base of the primary hydrothecse. 

Material : 

"Thor" 66°i9' N. 23°i4' W.; depth 115 -120 metres 

Greenland: Egedesminde (without further details) 

Iceland: 9 miles N.74°E. of Hornet, depth 38 fathoms 

Vadlavik, — 80 — [labelled Halecium leiielliim\ 

Djupivogr — 8 — | — — — ] 

64°i7' N., i4°44' W. — 75 metres [ — — — ] 

Skagi — 40 — 

Hvalfjord — 46 — | — — Schneiden] 

vSkjalfandi Bay — 28 fathoms. 

Kramp's studies (1913 p. 5) of Halecium minutum are highly interesting, He has succeeded 
in finding fertile female colonies, the identity of which is tiius placed bevond doubt, but where the 



HYDROIDA II 



51 




. 600 fTJ. 



Fig. XXII. Fiuds of HaUxium muititum in the Northern Atlantic. 

small sympodial parts, normal in appearance, arise from enormous rhizocaulome formations instead of 
from creeping stolons. This, as Kramp also points out, places the question of growth conditions as 
generic character in a remarkable light; and what is worse, it shows us that the shape of the colony 
can even in specific limitation only be applied with great discretion, a point which has also been 
noted here under the heading of Lo/oeidcr. Kramp thus supports my suppo.sition (1909 p. 153) that 
the colonies which Jiiderholm (1907) mentions from the Bering Sea under the name of Halcciuvi 
tflfscopicuiii should more probably be ascribed to HalccimJi iniinif/im. 

Halcciitm iiiinutiiiii is au arctic species which has doubtless a considerable distribution in tlie 
Polar Sea, but which is often confused with others, and especially witli Ilalecinm tcnelhim, as is also 
clearly evident from the list of investigation material given above. Apart from the Bering Sea, tlie 
species has been recorded at Spitzbergeu, the Murman coast, east and north coasts of Iceland, northern 
east coast of Greenland, and several places along the west coast; finally also Fraser (1913 p. 168) 
has met with it at Nova Scotia, on the Canso Bank. The species penetrates but very slightly into 
the boreal region, as far as can be seen from the finds made up to now. 



Family Plumulariidae. 

The hydrothecae are small, sessile, approximately radially symmetrical, one side partly or en- 
tirely fused with the branches (tubes); the diaphragm is somewhat asymmetrical. The large polyps can 
practically speaking never be drawn entirely into the hvdrothecse. The sarcothecse are two-chambered, 

7* 



rg HYDROIDA II 



stalked and mobile, or small, rudimentary or entirely effaced, being represented merely b>- holes in 
the periderm, at times with slighth- raised, asymmetrical edges. The margin of the hydrotheca is 
almost always without teeth. The colonies are monopodial with terminal growth point. The gastral endo- 
derm of the polyp is divided into a fore stomach and a digestive stomach part, the limit between them 
appearing as a constriction round the body of the polyp. 

As thus defined, the family covers the group Elentheroplea auctt. but it also further includes 
such primitive forms as Kirchenpaueria, which lacks true sarcothecse. What have been taken for such 
are in reality merely low, as a rule somewhat asymmetrically developed margins round the aperture 
in the periderm through which the sarcostyle passes out. This formation cannot be altogether regarded 
as a parallel to the sarcotheca, which forms the fixed point jof support for the sarcostyle, and is as a 
rule furnished with a diaphragm in Plnmulariidcc. 

On the other hand, it must be admitted that there are certain transition forms which render 
the limit between PlitmitlariidcF and AglaopheniidcE somewhat indistinct at times, as we find species 
with both stalked mobile, and immobile, sessile sarcothecse; these forms must be regarded as primitive 
Aglaopheniidce. Such transition forms are also met with as against HaleciidcE^ though it has not in 
this case been found advisable to unite the two families. We find, as a matter of fact, in almost every 
hydroid family such intermediate forms, the position of which is more or less a matter of doubt. If 
entirely definite boundary lines had to be drawn, it would very possibly involve the reduction of the 
entire group of hydroids to one or two families. But the heterogeneity would then be too great. In 
the same way, the Plunnilariidce, as viewed by Nutting (1900) and Stechow (1913) make a too 
heterogeneous group, which as both writers also admit, really comprises two ver)- well defined main 
groups. As these two main groups differ in principle, as much as any two families in the other 
family series of thecaphore hydroids, and as, moreover, the intermediate forms here are neither more 
numerous nor more marked than elsewhere, it will be correct to keep the two groups apart as sepa- 
rate families. 

Gen. Kirchenpaueria (Jickeli). 

Upright ])innate colonies, the stem bearing on its apophyses onl\- undivided branches (hydro- 
cladia) with several hydrothecae, these being unilaterally arranged, and fused with the branch. Beside 
the nutritive polyps appear the .sarcostyles, which proceed from holes in the periderm; these holes are 
often surrounded by a slightly raised, as a rule somewhat asymmetrically developed periderm collar. 
Paired sarcostyles lacking. 

Bedot (1916) reintroduces this genus, and defines it further in such a manner that the old 
Sertularia pinnata Linne appears as its typical species. 

In the list published in 1915, "Nomina conservanda. Unter Mitwirkung zahlreicher Spezialisten 
herausgegeben von Prof. C. Apstein" (Sitzungsberichte der Gesellschaft naturforschender Freunde, 
Berlin, Mai 1915) we find under polyps (p. 126—127) as type for Piumiilaria the Phuinilana pinnata 
L. This is well calculated to show that a list such as the one mentioned may easily manage to 
defeat its own ends. Within the very large number of species which are referred to the genus Phi- 
mularia^ the Plumularia pinnata takes up a quite exceptional position, owing to its reduced sarcothecse. 



HYDROIDA II „ 



which are partly or entirely lacking. If we were to follow the list, we should then be obliged, as Pro- 
fessor M. Bedot writes me in a letter on this matter, to alter the generic name for all the over 200 
species which have hitherto been noted under genus Pluinularia. There is, as Professor Redo t furtlier 
writes, nothing to suggest that Lamarck, the founder of the genus, ever regarded Plumularia pin- 
nata as the type species in preference to any other then known species of the genus. Tliere would seem 
much more reason to establish Pliimuloria sctacra as type species. That a generic distinctiou should 
be made between Plitnuilaria pinnata and the remaining species, where the sarcothecie are far more 
highly developed, and generalh- appear partly paired, is beyond all doubt; this Stechow (1913 p. 25) 
also points out, and suggests Kirc/iftipaufria as generic name for the group, but without going further 
into the matter. 

There are indeed several objections to be made to the mentioned list as regards the hydroids. 
That the authors note the genera Clytia^ Gonothyraca^ Pasytlwa, Podocoryiu\ and Schizotric/ia, may be 
taken for a party contribution to the dispute as to leading fundamental principles in systematics, whicli 
has no place in such a list, given without justification or explanation; the effect here is merelv to 
create confusion, not to form a basis for firm and tenable conditions. Here again there is no question 
of names rendered so familiar through the medium of the handbooks as to have any claim to acknow- 
ledgement on that count. Furthermore, the revival of a name such as Monocaiilus is more confusing 
than the retention of the later, generalh' employed appellation Bra7ichioccria>itliits. The authors liave 
here evidently failed to realise that the type species given, itiipcrator^ does not as a matter of fact 
occur at all in Allman's original Monocaitltis genus, which was founded on northern Corymorpha 
species with sessile gonophores, while the mentioned species was not found until later, by the "Chal- 
lenger", and incorrectly placed in the genus APonocan/iis, with the original diagnosis of which the spe- 
cies does not agree at all. We may further note the question as to whether Antoniularia or Ne7ner- 
tesia should be retained. The latter name is generally adopted in later works by Stechow, Broch 
and Billard, and is likewise recognised in Bedot's eminent historical nomenclature studies, and 
neither of the names can be said to be of o\'er frequent occurrence in the handbooks; the retention of 
AntoDiularia is here less due to sound defensible reasons than it is a matter of taste. — But we can- 
not here go farther into details with regard to this list; the foregoing will be sufficient to show that 
in its present form it is far from attaining the end proposed by discussion as to the retention of names 
whose alteration would bring about confusion in zoological handbooks and teaching works. 

As regards the generic name Kircheiipaueria, there may be some little hesitation. The name 
in question first appears as a synonym in Kirchenpauer's paper Neue Bryozoen, Catalog IVdes Museum 
Godeffroy, Hamburg 1869, where we find Kirc/icnpaiicria t'lcga>/s Greeff in litt. = Reichornia Greeffei 
Kirchenpauer. In the Bryozoa literature it occurs again only in E. C. Jelly, Synon\mic catalogue of 
the recent Bryozoa, London 1889, as Kirchenpancria elegans Graeffe, Kirch, in litt. — Jickeli introduces 
the name in 1883 for a hydroid which, as Bedot points out (1916 p. 641) is identical with Plumularia 
pinnata. Strictly speaking then, we should according to the precise rules of nomenclature perhaps 
rather have taken another name, but I regard it nevertheless as most correct for the present to follow 
Bedot, as there can hardly be any risk of confusion thereby. The generic name Kirchcnpaueria is 
therefore here maintained for the genus whose type is Scrtiilaria pi>i>iafa Linne. 



Kirchenpaueria pinnata (Linne) Bedot. 
1758 Sertnlaria pinnata, Linne, Systema naturse, ed. 10, jx 813. 
1916 Kirchenpaiieria pitivafa, Bedot, Sur le genre Kirchenpaueria, p. 645. 

Upright, singly pinnate colonies with monosiphonic or more rarely, in the basal part polysi- 
phonic stem. Hydrocaulus divided into internodia with one or several apophyses alternating to either 



54 



HYDROIDA 11 



side. The apophyses have each an unbranched hydrocladiuiii, divided by transverse joints into 
segments with numerous hydrotheca;. Eacli, or more rarely, every alternate iuternodium on the 
hydrocladium has on its distal half a hydrotheca entirely fused down its one side with the iuter- 
nodium, or more rarely having a low free adcauline edge. The hydrotheca-bearing internodia are also 
distally furnished with a median pore, proximally with a median pore having raised edges, through 
which the naked sarcostyles pass. The length of the hydrotheca varies between '/^ and '/s of that 
of the internodium. 

The gonothecte are situated on the stem or on the basal parts of the hvdrocladia, without 




Fig. XXII [. The distribution of Kirchenpmtoia pinnata in the Northern Atlantic. 
In the hatched regions a common occurrence is stated by the hterature. 

special protective organs. They are oval to pear-shaped, smooth or .spiny, often much flattened from 
the side. 

Forma iypica. Short internodia with hydrotheca; in length from '/j to '/^ the internodium. 
Forma eleganhda (G. O. Sars) slender internodia with small h>drothec£e, length as a rule from 
Vs to '/s of the internodium. 

Material (forma iypica): 

Greenland? (without further details). 

The Faroe Islands: (without further details) |= Pbi),mlaria ccJiinulala Winthcr|. 

The synonymy of the species has recently been worked out by BedotdgiG). It gives us an 
interesting insight into the variability of a .species, and throws a sharp light ui,on several of the 



HYDROIDA II 



55 



distinguishing features which have hitherto been regarded as good specific characters in Plumulariida;. 
There are undoubtedly, among tlie numerous recorded species of Pliimularia^ synonyms in abundance, 
and the new species and varieties which are constantly being described do not make matters better. 
New forms demand not only morphological but also other justification, as is the case with the forms 
liere noted. The variant group indicated as forma typica penetrates exceptionally [Plumularia Helleri) 
right into the Mediterranean, but has otherwise its main distribution in the boreal waters and in sub- 
antarctic regions, thus exhibiting a tendency to bipolar occurrence (cf. Broch 1914). Forma elegantula 
on the other hand, which is remarkable for its fine slender build, predominates under tropical-subtro- 
pical conditions, and is only on rare occasions met with in the temperate seas. 

The area of distribution for Kirchenpatieria pinna/a forma typica in northern waters coincides 
in the main with the fields on the chart (fig. XXIII); it is likely, however, that new finds will be 
made off the coast of Iceland, and we must wait until the species has been further localised in Green- 
land waters, before the query on the label can be erased. Kircheupaueria pintiala appears in the 
northern waters as less susceptible to diminished .salinity, and thus penetrates far up into the fjords; lower 
temperature, however, soon sets a limit to its progress. In the northern seas, it belongs to the littoral 
region, especialh' the upper half of the same, and only exceptionally occurs down in the abyssal. 



Gen. Plumularia (Lamarck). 

Upright, single or double pinnate colonies, the stem bearing on its apophyses undivided bran- 
ches (hydrocladia) with hydrothecse unilaterally arranged, and partly or entirely fused with the branch. 
The apophyse lacks sessile large sarcothecfe; the sarcostyles are situated in two-chambered mobile 
sarcothecse, generally a pair at the mouth of each hydrotheca. 

Plumularia setacea (Linue) Lamarck. 
1758 Serinlaria setacea, Linne, Systema naturae, ed. 10, p. 813. 
1 816 Plumularia setacea, Lamarck, Histoire naturelle, vol. 2, p. 129. 

Single pinnate colonies with monosiphonic main stem. The stem is divided into short mter- 
nodia, each with a distal apophyse, turned alternately to either side. Each apophyse has a hydrocla- 
dium divided by transverse joints into iuternodia, of which latter every alternate one bears a hydro- 
theca and three sarcothecse, and every other one or exceptionally two sarcothecse in the median 
line; the hydrotheca-bearing internodium has a proximal, median sarcotheca, and a supracalycine pair 
at the opening of the hydrotheca. The length of the h\-drotlieca varies between ',2 and V5 the length 
of the internodium. The h>-drotheca is fused throughout its whole length with the hydrocladium. 

The gonothecEe arise from the branch apophyse on the stem. They are elongated oval, with 
a cylindrical, narrow, often somewhat curved neck; the males are smaller than the females. The colon- 
ies are as a rule hermaphroditic, with the male gonangia on the basal part. 

Forma fypica: length of hydrotheca 'A— '/j the length of the internodium; the internodia com- 
paratively coarsely built. 



56 



HYDROIDA II 



Forma viicrotheca: length of hydrotheca '/4-V5 the length of the internodiuin; the internodia 
of slender build. 

Material (forma typicd): 

"Thor" 35°57' N., 5°35' W., deptli 740 metres 
Iceland: Vestmano, depth 50 fathoms. 

Plimmlaria setacea divides in the same manner as the foregoing into a widely distributed warm 
water variety, forma microt/icca, and a temperate forma fypica, occurring both in subantarctic and boreal 
waters. Plimmlaria setacea is in northern waters a denizen of the middle and upper parts of the lit- 




300 m. t 00 ryj. -,.. ___(000m. _.. „__.rooiJrn. 

Fig. XXIV. The occurrence of Plumularia setacea in the Northern Atlantic. 
In the hatched parts the occurrence according to the hterature is common, ahhough scattered. 

toral rugion, whereas in warmer seas it goes fairly deep down into the abyssal region. The species 
is altogether somewhat rare in the boreal area (fig. XXIV) and penetrates in considerable numbers 
only into the southern and warmest parts of the same. 



Plumularia Catharina Jolinston. 
1833 l^lumularia Catharina^ Johnston, Illustrations in british Zoology, p. 497, figs. 61 — 62. 

Upriglit, pinnate colonies with simple or branched, monosiphonic, little pronounced stem. The 
branches proceed from the base of tlie hydrothecse on the stem, and are as a rule placed oppositel)-, 
more rarely alternating. Stem and hydrocladia are divided into internodia by alternating transverse 



HYDROIDA II 



57 




and oblique nodes; above a transverse joint there is an intcrnodiuni bearing one or two unpaired 
sarcothecse in the median line, then the highly oblique joint, and an intcrnodiuni furnished with a 
proximal, unpaired median sarcotheca, a large hydrotheca, and two supracalycine pairs of sarco- 
thecas. Of the supracalycine pairs of nematothecae, the outermost is placed on small projecting apo- 
physes, the inner pair arises from the internodinm on the inner side of these sarcotheca apophyses. 
All the sarcotheca; are mobile. The Indrotheca is very slightly fused with the internodium, the 
adcladial side has a free portion, in length equal to the hydrotheca opening or a little less, between 
'/j and 3/^ the length of the hydrotheca. The hydrotheca is somewhat expanded towards the opening, 
and is able to accomodate the contracted polyp almost entirely. 
The gonothecse arise from the stem or the hydrocladia 
close beneath the hydrotheca:. The gonotheca is oval to pear- 
shaped, as a rule somewhat curved, the males a little more 
slender than the females. The female gonothecEe have basally 
two sarcothecEC, which, (according to Hi neks) are lacking in 
the males. 

Material: 

The Faroe Islands: 6 miles N. b)- W. of Store Kalso 

depth 6o fathoms 
Deep hole at the north point of Nolso, — lOo — 
Boronaes 13 miles in N. 75 W. — 30 — a 

Fig. XXV. Plnmuliiria Cathan'na 

The inner pair of supracalycine sarcothecie in Phiiiui- from 6 miles N. by w. of store Kalso. 

, . „ ,, . ,-. -irviTN ^1 1 *i it ff. hydrothecate internode seen from 

lana Catharuia (fig. XXV) appears to have escaped the atten- ^^^^.^^ _ ^ ^^^ successive inter. 

tion of most investigators; it is probably this pair of sarcotheca: noises in side view. - - i inner pair 

of supracalycine sarcothecae. (X Sol 
which has given rise to the distal median sarcotheca so often 

ascribed to the species. Such median (unpaired) distal sarcothecas I have been unable to find in the colonies 
at my disposal; not infrequently, however, one or both of the sypracalycine may have fallen away, rendering 
it difficult even to trace where they had been. It is remarkable that it should be the inner pair which exhibits 
such a marked tendency to fall off, exceeding that of the other sarcotheca;; the ones in question are, how- 
ever, also the smallest. In view of the abundance of the present material, and the fact that I found 
occasion also to investigate material from other parts of the Atlantic, we must regard the statements 
as to occurrence of an unpaired distal sarcotheca on the hydrotheca-bearing internodium in Pluiini- 
laria Catharina as based on incorrect interpretation of the inner pair of supracalycine sarcothecse. There 
can be no doubt that the species Pluniitlaria gcininata Allman, PliDinilaria alternata Nutting and 
Phimularia Ciarkei Nutting should be included under Plumularia Catliari)ia^ as I have already pointed 
out in a previous work (1912 p. 4); it is impossible to attach any weight to the characters given for 
specific distinction when once a larger material has been closely investigated. 

Plmnularia Catharina is a southern visitor to the boreal waters (fig. XXVI); round the British 
Isles it still seems to be of fairly frequent occurrence, but off the coast of Norway it is but little met 
with, and has only once lieen recorded from the south coast of Iceland. At the Faroe Islands, the 

Tile Ingolf-Expedition. V. 7. " 




58 



HYDROIDA II 




Fig. XXVI. The distribution of Phimularia Catharina in the Northern Atlantic. 
In the hatched parts the literature notes a common, although scattered occurrence. 

species seems to be somewhat more common than wonld appear from earlier records; at the two loca- 
lities noted here, it was present in great numbers. In Greenland waters, Plumularia Catharina has 
not yet been found. It belongs especially to the upper half of the littoral region. 



Gen. Polyplumaria' G. O. Sars. 

Upright, composite pinnate colonies with polysiphonic branched stem. The apophyses of the 
stem (the primary tube) bear hydrocladia from which secondary hydrocladia proceed, as a rule from 
the first hydrotheca-bearing internodium. The apophyse lacks sessile sarcotheca. All the sarcothecae 
are mobile and two-chambered. 

It is not witliout liesitation that I retain this genus beside Pliinutlaria^ with which it is closely 
related; it may be a question whether we should here, more than in other cases, base the generic 
division upon the form of ramification. That I have retained it for the present as a separate genus 
is due to the fact that its species, from their peculiar appearance, form a well-defined group, sharph- 
distinguished from the remaining ones which have been included in the genus Plumnlaria. My 
material is not so extensive as to suffice for a revision of the entire family, a task which becomes 
more and more nnperative as further species continue to appear in the literature. A work such as 

' Nutting has (1900 p. 83) by a slij) of the pen called the genus Polyptnmiilaria. 



HYDROIDA II -g 



that of Nutting (1900) shows more than most how absolutely indispensable such critical revision 
really is. It is therefore most correct here for the present to retain a genus such as Poly phi mar in. 

Polyplumaria frutescens (Ellis et Solander). 
1786 Scrtnlaria frutescens^ Ellis and Solander, The natural history of many curious and unconnnon 

Zoophytes, p. 55, pi. 6, fig. a. A, pi. 9, fig. i. 

The colonies are upright and singly or doubly pinnate, with polysiphonic hydrocaulus. The 
primary stem tube bears on its front a series of hydrothecse, one to three on each internodium ; at tlie 
base of each hydrotheca, the tube has an apophyse, which is directed obliqtieh- forward and to the 
side, alternating to either edge. The apophyse bears a h\drocladium, as a rule secondarily branched, 
which is at first directed obliquely upward and forward, but gradually turns into the broad plane of 
the colony. The hydrocladium is divided by transverse nodes into internodia, bearing one to several 
hydrothecse, and around this a pair of supracalycine sarcothecce, and one median, unpaired, under the 
base of the hydrotheca. The hydrotheca is fairly large, slender, and fused throughout the whole of 
one side with the internodium. The secondary hydrocladia proceed from under the base of the basal 
hydrotheca of the primary hydrocladia, and assume the same appearance as the primary hydrocladia. 

The gonotheca; are set on the branches without special protective organs. They are pear- 
shaped, cut off obliquely distally, with a large lid-bearing opening. 

Material : 

"Ingolf" vSt. 54 63°oS' N., i5°4o' W., depth 691 fathoms 3,9° 
- - 55 63^33' N., i5°o2' W., - 316 - 5,9^ 
The Faroe Lslands: 6i°4o' N., 7'"4o' W., — 135 — 

16 miles E. by S. of the south point of Nolso, depth 80 fathoms. 

Polyplumaria frutescens has its chief occurrence in the lower parts of the littoral region, and 
in the upper portion of the abyssal. It is a southern visitor to the boreal seas, having only on a 
single occasion been encountered in colder water layers, viz. east of Iceland (fig. XXVII). In Green- 
land waters, the species has not yet been found, and its occurrence at the Faroe Islands is here recorded 
for the first time. 

Polyplumaria flabellata G. O. vSar.s. 
1874 Polyplumaria flabellata, G. O. Sars, Bidrag til Kundskaben om Norges Hydroider, p. 93, pi. 2, 

figs. 16—22. 
Upright, doubly pinnate colonies with polysiphonic branched main stem. The primary tube 
bears on its internodia alternating apophyses, directed obliqueh' forward and upward. From the apo- 
physe proceed the primary hydrocladia, which soon curve into the broad plane. The hydrocladia are 
divided by almost transverse nodes into internodia, each bearing a large hydrotheca, a pair of supra- 
calycine sarcothec^e, a larger, unpaired proximal, and a smaller unpaired distal sarcotheca in the median 
line. The hydrothecse are fairly large, about half as long as the internodium; the adcauline wall has 

a free portion in length about equal to the opening diameter, between one and two thirds of the length 

8* 



6o 



HYDROIDA II 




Fig. XXVII. Localities of Polyplumaria frutescens in the Northern Atlantic. 
In the hatched parts the Uterature notes a scattered occurence without further data. 

of the hydrotheca. The .secondary hydrocladium proceeds from beside tlie basal hydrotheca of tlie 
primary hydrocladium, and is of the same appearance as this. 

The gonothecse are fastened to the stem or the branch apophyses by a very short stalk. They 
are oval, with a large, somewhat asymmetrical distal opening, and with four sarcothecae at the base. 
Material : 

"Thor" 35"57' N., 5°35' W., depth 740 metres 

Iceland: Vestmano, — 510 — 

According to Ritchie (191 1 p. 223) the number of unpaired small distal sarcotheca; on the 
internodinm .should vary from one to three. No such variation could be discerned in the colonies 
investigated by me. 

Polyplumaria flabcllata is a very rare visitor in the northern waters (fig. XXVIII) and occurs 
here only in the deeper water layers. The species has altogether its main distribution in the upper 
parts of the abyssal region. The Vestmanna Islands mark the most northerly point where it has been 
found up to now; in Greenland waters it would seem to be entirely lacking. 



Polyplumaria profunda (Nutting). 
1900 Plumularia profunda. Nutting, Phnnularidae, p. 66, pi. 8, figs. 2—3. 

Upright, composite pinnate colonies with branched polysiphonic main stem. The primary tube 
which is seen in the outer parts of the colony is divided by transverse nodes into internodia, bearing 



HYDROIDA II 



6i 




ioo m 6000. looom. jooom 

Fig. XXVIII. Finds of Polyplumaria flabellata in the Northern Atlantic. 

one or two alternating apophyses. The apophyse proceeds asymmetricalh' from the base of a cauline 
hydrotheca; this is surrounded by a pair of supracalyciue sarcothecas, and a third sarcotheca situate 
proximally and a little to the side of the median line, somewhat removed from the base of the hydro- 
theca, on the side of the median line opposite to the apoph)'se. The hydrocladia are divided by trans- 
verse nodes into internodia, which have about the middle a hydrotheca with a supracalyciue pair of 
sarcothecse, on low apophyses near the opening of the hydrotheca, and a proximal, unpaired sarcotheca 
in the median line near the proximal end of the internodium. The basal internodium on the primary 
hydrocladium has two proximal unpaired sarcothecje in the median line; 'at the base of this inter- 
nodium's hydrotheca there appear, in fertile colonies, apophyses to the secondary hydrocladium, which 
is of the same structure as the primary. The hydrothecce are on the hydrocladium about twice as 
long as broad; on the stem somewhat shorter; the}- have a somewhat outward curving opening margin, 
and are fused throughout their whole length with the internodium. 

The gonothecse are situate on the stem or close under the base of the proximal hydrotheca; 
on the primary and secondary hydrocladia; they have a short, often rudimentary stalk. The gonothecse 
are pear-shaped, often curved, rounded off somewhat asymmetrically distally, with a broad opening; 
they have two sarcothecse basally. 



Material : 



"Ingolf St. 24 63°o6' N., 56°oo' W., depth 1199 fathoms 2,4° 

- - 55 63°33' N., i5°02' W., - 316 - 5,9° 

- - 98 65 38' N., 26^27' W., - 138 - 5,9° 



62 



HYDROIDA II 



That Nutting (1900 p. 66) should refer this species to Plmini/aria must be due to his having 
had small or poorly developed colonies to deal with. From the "lugolf" St. 55 we have a couple of 
splendid colonies showing the typical secondary hydrocladia of Polyplumaria in practically ever)- branch, 
and richly furnished with gouangia. These are situated on the basal part of the hydrocladia — both 
primary and secondary, and partl\- also on the tubes of the stem. 

It might be imagined that the present specimens, with their typical Polyplumaria colonies, 
were specificallv different from Nutting's Pin iimlaria profunda. We found, however, besides the two 

mentioned, extremely luxuriant colonies, also a smaller, single 
pinnate colony, where only the basal hydrocladia were furnished 
with secondary hydrocladia, all the remaining hydrocladia being 
simple. Nevertheless, this colony is likewise fertile, and a fur- 
ther investigation of the larger colonies shows that here also 
the secondary hydrocladia are lacking on several branches. In 
all these colonies, the stem is polysiphonic. But from the "In- 
golf St. 24 we have a quite young, sterile colony, where the 
whole stem is monosiphonic; only at the bottom of the basal 
part is a secondary tube developed. Here then, we have the 
complete transition from Nutting's description to the typical 
iiiaria which the species represents in its full)' developed 
form. The resemblance in detail will furthermore be seen from 
a comparison of the illustrations here given (fig. XXIX). 

The finding of Polyplioiiaria profunda in the northern 
Atlantic is highly interesting. The species is a typical deep sea 
form, previously known only from West Indian waters. We now 




V 




\ ^ Poly pi HI 



a Fig. XXIX. * 

Polyplumaria profunda "Ingolf ' St. 24. 

a. Hydrocladial inteniodium. b. internodiuiii find, that it penetrates in deep water right up into Davis Strait 

of the priiiiarv stem tube, with apophvse. (X6o). ,„ , r^ ■ ■, , , ^ r-irii 

and Danmark Strait, and to the southern slope of the Iceland 
region, where the warm and salt Atlantic water predominates. It is evidently not able to pass over 
the submarine ridges or into strictly boreal waters. 



Nemertesia Lamouroux. 
Upright colonies with as a rule pronounced main stem, which may be branched or uu- 
branched, generally articulated and furnished with strong apophyses bearing finely built hydro- 
cladia. The hydrocladia are single, unbranched. The colonies are furnished with stalked, two-chamb- 
ered and mobile sarcotheca;, and have in addition, on each apophyse at its upper side where it pro- 
ceeds from the stem, a large sessile sarcotheca ("mamelon"). The h)drocladia are segmented, and have 
several hydrothecse, which as a rule are fused throughout their entire length with the branch. The 
hydrocladia are generally situated in several rows in fullv developed colonies. 

Formerly, in drawing the limits for this genus, the principal stress was laid on the fact that 
the hydrocladia are in multiserial arrangement, not merelv in two rows as in Plumularia. This cannot 



HYDROIDA 11 



63 



however, be admitted as a particularly important feature in generic distinction, as will be seen from a 
closer study of the Nemertesia species and their development. A species such as Nemcrlesia tetrasticlia 
(Menegliini) differs in reality but little from the pure Plumularia type, its four-rowed appearance being- 
due to a slight alternating displacement of the apophyses on the two sides; we have here then, as a 
matter of fact, two-rowed colonies, which have probably when younger been of the pure Plumularia 
form. In Nemertesia ramosa (Lamarck) I have in a previous work (1912 p. 5) pointed out that the distal 
parts of the colony not infrequently exhibit a purely biserial arrangement of the hydrocladia; the 
present material shows that small colonies both of this species and of Nemertesia antennina (Linne) 
are altogether biserial. Here, as a matter of fact, it is quite another character which warrants the 
generic identity, to wit, the large sessile sarcotheca ("mamelon") of the apophyse, which occurs in the 
colonies from the earliest stages onwards. 

The development of the colonies, and the grown colonies themselves, clearly show that the 
multiserial arrangement of the hydrocladia is a secondary adaptation which is, moreover, in many 
species, subject to great variation within one and the same colony. The number of branch series is 
even variable in the single species, as in Nemertesia ramosa^ where it varies from two to eight, or 
Nemertesia antennina^ where we find from four to twelve. It is not easy to see why it should be 
more reasonable and effective to draw the limit between biserial and multiserial than for instance be- 
tween quadriserial and multiserial. On the other hand, there is one constant feature in all the species 
hitherto noted under this genus; to wit, a peculiar large sessile sarcotheca on the apophyse. A com- 
parison with other species (see for instance more particularly AglaopheHopsis cornuta) suggests that 
this formation should in reality be regarded as an abortive hydrotheca. In most cases, it forms a 
rounded raised portion, with circular opening, happily described by the French writers as a "mamelon". 
This sarcotheca occurs in colonies from the smallest to the largest in the same manner, whether the 
species is biserial or multiserial. It must thus be regarded as of generic importance. Consequenth', 
we must reject from Plumiilaria those species which are furnished with a "mamelon" on the apophyse 
and have unbranched hydrocladia, placing them instead under Nemertesia. 

We thus obtain, in this genus, biserial and multiserial forms. It is impossible to determine, 
from the data available, whether a species like Nemertesia caulitheca (Fewkes) (= Plumularia cauli- 
theca^ Nutting 1900 p. 63) is a \oung stage or not; its gonangia have not yet been discovered, and it 
may possibly be found to go through a development similar to that of our northern species, passing 
gradualh- from a biserial type over into the multiserial form. If not, then it must be regarded as a 
primitive species. The next stage is represented by Nemertesia tetrasticlia (Meneghini), with its alter- 
nately displaced apophyses in the two branch rows; Nemertesia raiiiosa undergoes this stage, and 
probably also Nemertesia antennina, the former, however, at any rate soon proceeding further with a 
marked twist of the internodia, so that the apophyses in one internodium are perpendicular to those of 
the previous and subsequent ones. Not until later do further apophyses appear at the same level as 
the first, and from now onwards we regularly find, owing to the revolved position, a number of branch 
series divisible b>- two. 

The nature of the stem has also served as basis for a division of the genus; here again, how- 
ever, there is no real difference of principle to work on. The younger stages of Nemertesia ramosa 



64 



HYDROIDA II 



have monosiphonic stem; not until later does it become canaliculate, and finally, in fully developed 
colonies, we find purely polysiphonic basal parts of the stem, where secondary tubes cover the canali- 
culate central tube. Thus the limits between Nevu-rtcsia and Antennopsis become effaced, and these 
genera must in consequence, as I have previously maintained (1912 p. 28), and as Stechow also points 
out (1913 p. 25) be united into one. Similarly it follows, that Stechow is correct in placing Sibogella 
under Ncmeriesia. 

Bedot, in a work which has just appeared (1917) treats of the genus Nemertesia at length, 
unfortunately, however, without giving any synopsis of the generic characters. It is nevertheless clear 
that Bedot inclines to regard the canaliculate ("pluricanaliculee") stem as a family trait. The char- 
acter is developed, as mentioned above, only in somewhat 
larger colonies — generally at least 5 cm high — it is 
moreover often lacking in large distal parts of the 
colony in the northern species, where the stem fre- 
quently retains its primary ("unicanaliculee") character. 
And finally, the primary "pluricanaliculee" stem tube 
is secondarily covered, as in Nemertesia ramosa^ by 
tubes "unicanaliculees" to a greater or lesser extent. 
This in itself detracts from the value of the character 
in question. But in addition, it is also found to stand 
in a certain relation to the dimensions of the stem 
tube; thick, single stems are "pluricanaliculees" in spe- 
cies within the same genus, where the thin ones are 
constantly "unicanaliculees" (cf. for instance Tiibularia). 
, As a matter of fact, the two types "fasciculee" (poly- 
siphonic) and "pluricanaliculee" (canaliculate) represent 

Fig. XXX a— f. A'fOTiT/w/a a«<^««(«o. juv. "Ingolf vSt. gS. parallel processes of development towards the same 

a. The entire colony (nat. size). — b. Internodiuni of the j a j ui .-„ *-„i „ 4-1,^ 4^„,™^r 

, J , .,,,,,,,., , , • ,, end. And as we are unable to take the former 

hydrocaulus with the hydrocladial apopnyse, showing the 

sessile sarcotheca. — c. Two successive internodes of a as basis for eeneric distinction, SO also the latter 
hydrocladium [h and c x 80). . . 

character must be considered quite inadequate as a 

iiicaus of distinguishing between genera (or families). 





% 



Nemertesia antennina (lyinne) I^amouroux. 
1758 Sertularia antennina^ lyinue, Systema uaturcC, ed. 10, p. Sti. 

1812 Nemertesia antennina^ Laiuouroux, Extrait d'uu memoire sur la classification des polypes coralli- 

genes, p. 184. 

Colonies with unbranched or tiuite exceptionally slightly branched canaliculate and segmented 
stems. The apophyses are set in circles on the internodiuni, each circle containing three to six or 
even more apophyses; the internodia are revolved, so that the stem has twice the number of longitu- 
dinal rows of apophyses. Near its point of origin, the apophyse has 011 its upper side a comparatively 
small, sessile sarcotheca ("mamelon") and two or three irregularly arranged, stalked and two-chambered 



HYDROIDA II 



65 



mobile sarcotheca;. The liydrocladia are divided by transverse nodes into internodia of which nornialh' 
everv second one bears one or two nnpaired sarcothecK in tlie median line, the alternate ones having 
a small hydrotheca with a snpracalycine pair of sarcothecae at the month, and an nnpaired median sar- 
cotheca on the proximal part of the internodinm. The hydrotheca is abont '/^ to ',3 the length of the 
internodinm, and is on one side entirely fnsed therewith. 

The gonothecoe are attached b)- an almost rudimentary stalk to the apophyses; they are oval 
to pear-shaped, with a distally laterall)- placed asymmetrical opening. 




200 m. _. 6oont tooo m. ,_ 2ooom. 

Fig. XXXI. The distribution of Nemertesia antenttnui in the Northern .\tlantic. 
In the hatched parts the literature notes a scattered although common occurrence. 

Material: 

"Ingolf" St. 87, 65°o2,3' N., 23°56,2' W.; depth no fathoms 

- - 92, 64°44' N., 32°52' W.; - 976 - 1,4° 

- - 98, 65^38' N., 26^27' W.; - 138 - 5,9° 

Greenland: Davis Strait, — 80 - (without further details) 

_ _ 65°27'N., 54^45' W.; - 67 - 
Iceland : 5 miles E. of Seydisfjord, — 135 — 

The Faroe Islands: Deep hole at the north point of Nolso, depth 100 fatliom.s. 

Some luxuriant colonies from Davis Strait exhibit interesting variations in the number of 
hydrocladia. The nodes of the stem are .slightly marked, and each internodinm bears but three apo- 
physes; owing to the revolution of the internodia therefore, the.se colonies or parts of colonies are six- 
rowed; among these colonies again there are others, or in the single colony, otlier parts, which 111 a 



The Ingolf-Exptttiiion. V. 7. 



56 HYDROIDA II 



similar manner appear eight-rowed, with four apophyses in the circle. The same octoserial type was 
met with at the "Ingolf St. 87, and from vSt. 92, we liave for the first time specimens with six apo- 
physes in each circle, giving a twelve-rowed colony. The revolution of the segments is thus charact- 
eristic of grown colonies, and calls to mind the features noted in Nemertcsia raniosa (cf. Rroch 
1912 p. 51. 

From vSt. 98, the "Ingolf brought a young specimen of Neiiirrffsia antenni)!a which is of con- 
siderable interest (fig. XXX). The colony is still quite biserial, and can only be distinguished from 
Plumularia by the sessile "mamelon" of the apophyses. As howe\er, the arrangement of the sarco- 
thecse and hydrotheca; entirely agrees with Nemcrtesia diifffuiii/a, I have no hesitation in referring 
the colony to this species, the more so since altogether parallel stages occur in the following species 
together with later phases of development. 

Nemertcsia antennina is a southern form with wide distribution in the boreal region (fig. XXXI). 
Towards the south, it goes at an\- rate as far as Madeira, and is common in the Mediterranean; it 
belongs to the middle and lower parts of the littoral region, but may exceptionalh', as shown b\' the 
finds from the "Ingolf St. 92, go deep down into the abyssal. It has not >et been met with in purely 
arctic waters, unless the one find from the east coast of Iceland should be so described. 

Nemertesia ramosa Lamouroux. 
1816 Neviertesia raviosa, Lamouroux, Histoire des Polypiers coralligenes, p. 164. 

1903 Anfe.n)iiilaria variabilis^ Broch, Die von dem norwegischen Fischereidampfer "Michael Sar.s" 

gesammelten Hydroiden, p. 10, Taf. IV, figs. 22 — 25. 

Colonies with branched main stems, polysiphonic in tlieir lower parts, canaliculate in the upper. 
Apophyses form circles about the internodia of the stem, two to four in each circle, and the internodia 
are revolved, giving twice the number of longitudinal rows. In the lower parts of the colonies, where 
secondary tubes cover the primary stem, the circular arrangement of tlie branches is less distinctly 
marked. The apophyse has on its upper side a strong, narrow, but high sessile sarcotheca ("mamelon") 
and 3—4 irregularly placed, mobile sarcothecse. The hydrocladia are divided by transverse nodes into 
internodia, each of which has a median hydrotheca with a supracalycine pair of sarcothecse at the 
opening, and one proximal and one distal unpaired sarcotheca in tlie median Hue; exceptiouallv, the 
distal part with its sarcotheca may be divided by a slight joint from the main internodiuni. The hy- 
drotheca is entirely fn.scd with the hydrocladium, and is ' '„ to '/, the length of tlie iuternodium. 

The gonothecte are attached to the apophyse by a short, almost rudimentary stalk. They are 
oval to pear-shaped, with a distally lateral asymmetrical opening. 

Material : 

"Ingolf St. 55 63°33' N., i5°o2' W.; depth 316 fathoms, 5,9 

- - 85 63-21' N., 25°2i' W., - 170 - 

"Thor" 61 = 15' N., 9°35' W.; - 872 metres 

Iceland : Vestmano, _ 50 fathoms 

The Faroe Islands: 62°i6' N., 6°o6' W.; — no metres 

6o°55' N., 8^=56' W.; - 840 - 



HVDROIDA U 



67 



6 miles N. by W. of Store Kalso. depth 60 fatlioins 

Deep hole at the north point of Nolso, — 100 — 
1,5 — 2 miles off the month of Borovig;, — 20—30 — 
Provenaes 13 miles in N.75°W., — 30 — 

Boronses in N.75°W., — 30 — 

The Faroe Islands, ■ — 30 — ' 



(without further 
details). 



Nemrrfrsia ramosa is extremely variable as regards arrangement and number of the ludrocladia, 
as I have previonsl)- {1912 p. 5) had occasion to explain. In the revolution cjf the interuodia, however, 
it follows the same regular principles as Nnnertcsia aiiteiuiiiia. The structure of the stem presents 






Fisf. XXXIl. Ni-tmrtt'sia rnmosa juv. <;. Young colony from "Ingolf St. 55 
(nat. size), b. hydrocladial internode from the same colony (X8o). c. apophyse 
from the same colon}'(X So), d. colony from "Ingolf St. 85 (nat. size', e. apo- 
b physe from the colony from St. 85 (X 80). 

features of considerable interest. The distal part of its ramifications exhibits the same structure as 
Nemertesia antcnnhia, having, inside the homogeneous peridermal chitinous^sheath, coenosarc strings; 
these parts of the stem are thus canaliculate. Farther down, however, we find secondary tubes closely 
arranged about the primary stem tube, and the nearer we come to the base, tlie closer is the network 
and the thicker the stem. Where these secondary tubes occur, they co\er the apophyses more and 
more, finally burying them altogether, while the hydrocladia here also fall away. Consecpieutly, the 
basal part of well-developed colonies of A^cmertesia ramosa lacks hydrocladia, wherel^y the colon)- assumes 
a highly peculiar appearance. 

At a couple of the "Ingolf" stations, some quite small colonies of Nemertesia. ramosa were 
found; these serve well to show the difficulty of distinguishing the young stages from Plumnlaria 
(fig. XXXII). The smallest colony [a] is altogether pinnate; the thin stem is divided into irregular 
internodia with a varying number of apophyses, but closer investigation shows that the apophyses 
do not form two regular longitudinal rows, being as a matter of fact alternatel\' somewhat displaced 
to one side or the other, so that we have here a slight approach to quadriserial arrangement. A some- 
what larger colony (</), where the stem is slightly thicker, reveals more clearly the displacement of 

9* 



68 



HYDROIDA II 



the apophyses, which is here evident at the first glance. In this case, it would scarcelx- be possible 
for anyone to doubt that the specimen is a young Nemcrfesia^ the more so since the stem is strikingly 
tliick. Furtlier confirmation is in both instances afforded by the branch apophyses (c and e)\ in both 
colonies we find the characteristic "mamelou" on the upper side of the apophyse, close to the stem, 
wliich proves that the>- belong to the Ncincrtesia. The entire arrangement of the hydrothecae and 
sarcothecae also shows that the species is Ncvicriesia rainosa. 

The stages found already show that the younger Nemertesia are throughout constructed after 
the PluDiularia type, with biserial apophyses, and that Semertcsia must be derived from Pliiuntlaria. 
It would further seem to suggest that Plunmlaria caulithcca Fewkes is probably a young stage of a 




200 m. 6ocm. (000 m. looom. 

l-'ij,'- XXXllI. Occurence of A'rm<'ftesia raniosn in the Northern Atlantic. 
In the hatched region the literature notes a common occurrence. 

Nemertesia. And it is likely tliat also other Plunmlaria species in reality cover young Nciiicrfesia 
species, and slionld, from the presence of a;"mamelon", be transferred to that genus. 

Among the synonyms of Nemertesia raiiiosa should also be reckoned Anteniiularia variabilis 
Krocli. The defective specimens, where only tlic chitinous parts are preserved, have lost all their 
sarcothecK, so that only a hole in the periderm, or a slightly raised part here and there, shows where 
the sarcothecae have been. The difficulty of discerning these remains has led to their being regarded 
as variable in number, and the remains or traces of supracalycine sarcotheca; had altogetlier escaped 
attention. Otherwise the colonies agree entirely with Nemertesia rainosa, and must thus be referred 
to that species. 

Nemertesia ramosa has its cliief occurrence in the littoral region. e.speciall\- in the middle and 



HYDROIDA II 



69 



lower parts of the same; it has been met with once or twice quite deep down in the aljyssal region, 
as for instance on the "Tlior" expedition, when it was taken near the Faroe Islands at 872 metres, 
probabh- the greatest depth from which the species has hitherto been recorded. Nonrrtcsia ramosa 
belongs to the warmer parts of the Atlantic, and penetrates thence (fig. XXXIII) in great numbers 
into the southern part of the boreal region. The species has not hitherto been found in Greenland 
waters, but is recorded fiom one or two places on the .south coast of Iceland. Round the Faroe Is- 
lands, it is seen to be of very frequent occurrence, and is said by Hincks (1868 p. 283) to be more 
numerous even than Srniertesia a?ifefi7iii!a on the coasts of Scotland. The species has not yet been 
located with certainty on the Norwegian coasts, but its occurrence in the Skagerak (Broch 1905 p. 
241 and Bohuslan (Jaderholm 1909 p. 105) suggests that it will probably be found to occur there.' 

Polynemertesia nov. gen. 
Upright colonies with distinct, branched main stem, exhibiting segmentation in its monosipho- 
nic parts; the stem is furnished with alternating strong apophyses which bear finely built hydrocladia. 
The hydrocladia are secondarily branched. The apophyses — both those of the primary and those of 
the secondary hydrocladia — are furnished on their upper side, near the point of origin, with a 
short sessile sarcotheca, "mamelon"; all the remaining sarcothecte are mobile. The primary and .se- 
condary hydrocladia are segmented, and bear several hydrothec;e, which are as a rule fused through- 
out their entire length with the branch. 

It is with considerable hesitation that I have established this new genus for Pluiiiularin gra- 
cillima G. O. Sars. Previous investigators have overlooked the presence of a "mamelon" on the apo- 
physes, in virtue of which the species must be separated from the Pbttiinlaria. With its secondary 
ramification of the hydrocladia, however, the species stands in the same relation to Neviertcsia as 
PolypluHiaria to Plumiilaria. A separation of the two latter genera therefore logically demands a 
like separation between the parallel groups of Nenicrfesia and PolyncDicrtesia. The fact that the prim- 
ary apophyses in the only known species are biserially arranged on the hydrocaulus must be regarded 
as of minor importance. 

It might be thought more reasonable here to revive an older name for the genus in question; 
it should then be Diplopteron or Scliizotyiclia. The former, however, has already been withdrawn by 
Allmann himself I1883 p. 30) as synonymous with Polyplitiiiaria\ N utting's attempt to revive it (1900 p. 
81) can only be explained as due to his having taken as basis for the generic division a character 
which should otherwise be used only with caution even in distinction between species, as in all pro- 
bability, it would seem that the type species for Polypluviaria and Diplopteron are very nearly identi- 
cal. And with regard to Schizotrichn it .should be borne in mind that both the two species originally 
placed by Allman (1883 p. 28) in this genus must be referred to Polypliimaria. It would thus be 
incorrect to take as the type a species which has not from the first been ascribed to this genus; Phi- 
ntularia gracilliina G. O. Sars is first placed under this head by Nutting (1900 p. 80). Of the remain- 
ing species which have been referred to this genus, Schizotricha bifitrca Hartlaub and Schizotrtcha 

■ After the tlo.se of the manuscript a find of the species in the Trondhjeni fjord has i)roved the correctnes of this 
supposition. 



70 



HYDROIDA II 




!? 



antarctica Jaderholm must doubtless be removed to a genus of their own, more closely related to 
Kirchenpaucria. It would thus not be advisable to introduce a new diagnosis for Schizotricha; the 
genus should rather be allowed to disappear definitely as synonymous with Po/yplumaria, which latter 
generic appellation is older, and originally better defined. For Fhimiilaria gmcilUwa G. O. Sars there- 
fore, it will be best to take an entirely new generic name. 

Polynemertesia gracillima (G. O. Sars). 

1873 Plumiilaria gracillima, G. O. Sars, Bidrag til Kundskaben om D\relivet paa vore Havbanker, p. 86. 

1893 Plunmlaria groenlandica, Levinsen, Meduser, Ctenophorer og Hydroider, p. 63, tab. VIII, figs. 10—12. 

Single pinnate colonies with 
monosiphonic or in the basal parts 
polysiphonic main stem. The mono- 
siphonic stem is divided by trans- 
verse nodes into internodia, which 
bear distally a short apophyse, di- 
rected obliquely forward, turning 
alternately to either side of the me- 
dian line. The stem has no hydro- 
thecie, but bears mobile sarcothecse, 
two unpaired, somewhat asymme- 
trically arranged on the basal part 
of each internodiuni. The apophyse 
has a "mamelon" on its upper side 
near the stem; beside this on the 
rear side a mobile sarcotheca, and 
))). \ t;;„ ywt^t r> I / ■ -u- f,.„„, ft,» no,-;., Qtvojf also an unpaired mobile sarcotheca 

'■ ' ' ■' I'ig. XXXIV. Polynemertesia gracillima from the Uavis btrait i 

\\.y\)t =^^^ii\\n^\\ oi Pliimularia groenla)idica\ rz. Internodium of the clistalU' iu the median line. The 
stem with primary apophyse. b. Second internode of a priiii- 
" ary hydrocladium with secondary apophyse, showing a distinct apophyse bears a seconclarily bran- 

"mamelon". .. Hydrothecate internode. (X 80). ^j^^^ hydrocladium; the hydrocla- 

dium is divided by transverse nodes into irregular internodia, of which every alternate one bears two 
unpaired sarcothecai in the median line, every other a median hydrotheca, a supracalycine pair of sar- 
cothecce at the opening of the .same, and an unpaired proximal, and as a rule an unpaired distal sarco- 
theca in the median line; on the distal parts of the hydrocladia the hydrothecaless internodiuni often 
melts into the hydrotheca-bearing internodiuni. The basal internodinm of the hydrocladium is hydro- 
theca-bearing; the following small internodiuni is furnished at the middle with an apophyse directed 
obliquely forward and bearing the secondary hydrocladium; from the second segment of the latter there 
proceeds as a rule a further hydrocladium in the same manner; these secondary (tertiary) apophyses 
also are provided with a "mamelon" and two mobile sarcotheca;, as in the case of the primary apo- 
physe. The secondary hydrocladia are of the same structure as the primary. The liydrothecEe are 
small, with slightly outward curving opening margin, and are throughout tlieir entire length fused 
with the internodinm. 




" 



IIYUROinA 11 



71 



The gonotlieciie are attached to the apophyse beside tlic sessile sarcotheca. Fully orown gon- 
aiigia have not yet been found. 

Material : 

"Ingolf" St. 27 64°54' N., 55° 10' W., depth 393 fathoms 3,8° 

- - 34, 65°i7' N., 54^17' W., _ 55 _ 
Greenland: Davis Strait (without further details) [type specimens of Pbmmlaria groenlandica\ 
Iceland : Ingolfshcifdi q' /j miles in N. by E. '/j E., depth 53 fathoms. 

Levinsen (1893 P- '^3) gives a very detailed description of this species, which he incorrectly 
regards as different from vSars's Pl/tii/iilan'a gracilliuia. He has however, in common with others who 




2 00 m. »_„ 600 m. .. loQO m. 2 000 m. 

Fig. XXXV. The localities of Polynemertesia gracillima in tlie Northern .-Vtlantic. 
In the hatched region the occurrence according to the literature is common, although scattered. 

have investigated the species, overlooked its typical sessile sarcotheca on the apophyses (fig. XXXIV) 
It is noticeable that a mamelon occurs not only on the primary but on all the apophyses in the colony. 
The idea that it should, as Nutting (1900) believes to be the case with other species, form the point 
of origin of the gouothecse, is due to inadequate investigation; the gonothecas have their point of 
attachment by the side of this sarcotheca. Levinsen's description incorrectly gives the impression 
that he has had grown gonothecae before him at the time; they are, however, only quite young stages, 
and grown gonangia have thus not been described for this species. 

Polynemertesia gracilliuia is plainly- a southern visitor to the northern waters, and has strangely 
enough not yet been recorded in the British waters (fig. XXXV). The "Ingolf" was able to furni.sh 



-2 HYDROIDA II 



further data as to the occurrence of the species at West Greenland, where it penetrates right into the 
Lille Hellefiskebanke. On a single occasion it has been found in Iceland waters. On the coast of 
Norway it has been met with now and then between Lofoten and Stavanger. It has also been found 
off Bohuslan (Jaderholni 1909 p. 108). The species belongs to the lower part of the littoral region, 
and the upper parts of the abyssal. 



Family Aglaopheniidae. 

The hydrothecse are large, with distinctly bilateral structure, sessile, and with the one side 
wholly or partly fused with the branches. The diaphragma is assyninietrical or bipartite. The polyps 
can retire altogether into the hydrothecte. The sarcothecse are sessile, immobile and well developed; 
exceptionally we may find, in addition, also mobile, stalked supracalxcine sarcothecse. The hydrotheca 
margin is as a rule furnished with teeth. The colonies are monopodial with terminal growth point. 
The endoderm of the polyps is divided into a fore-stomach and a digestive part; the ectoderm often 
gives off an ectoderm lamella which fastens the polyp to the ribs of the hydrotheca. 

The division of this family is based chiefly upon tlie nature of the gonangia and the protective 
formations which are richh' and variously developed in the different genera. Primitive in this respect 
is Halicornaria^ from which the remainder are derived. On the one side, there is a development to- 
wards Nemato carpus^ where the hydrocladia are secondarily branched, though without discernible 
relation to the gonangia. On the other arise, in all probability separately, the phylactogonia-bearing 
genera Aglaophettopsis and Cladocarpus, typical deep sea genera, of which the former has hydrotheca- 
bearing pliylactogonia, the latter, on the other hand, only sarcotheca-bearing phylactogonia. Possibly 
also, the corbula-bearing genera Thecocarpus and Aglaophenia should be derived from these, but their 
origin is not yet certain. 

Gen. Halicornaria (Busk). 

Upright colonies with branched or unbranched main stem, the apophyses of which bear un- 
branched hydrocladia with several hydrothecse. All sarcothecse are innuobile. The gonangia are situate 
on the stem or branches without protective organs of any kind. 

Halicornaria campanulata (Ritchie). 
1912 Clndocarpiix [>) caffipatiula/iis, Ritchie, Some Northern Hydroid Zoophytes, p. 226. 

The colony is doubly pinnate, with polysiphonic branched main stem, which consists in its 
extreme portions of the primary segmented tube alone. This has internodia of medium length, which 
bear about the middle a short, but quite broad apophyse; the internodium is further provided with 
a pair of sarcothecse at the upper side of the apophyse, and an unpaired median sarcotheca in front at 
its lower side; the .sarcothecse are almost tubulou.s, adcaulinally split. The hydrocladia have on each 
internodium a broad, and not particularly large hydrotheca and three sarcothecse; a supracalycine pair 
at the opening, and a median proximally, which with its opening margin reaches up to the bottom 



HYDROIDA II 



73 



of the livdrotlieca. All the sarcothecas are adcaulinally split, and liave a sliglitly dentate margin. Thc 
hydrotheca is broad, and has a very slighth' curved opening margin; its basal part has a somewhat 
thicker wall than the distal two-thirds, and the boundary between the two portions is apparent as a 
fine line abcladialh' directed obliquely forward towards the opening; hydrothecal ribs or septa lacking. 
The internodium shows two to four inner ribs at the adcladial side of the hydrotheca; one such, which 
is three-branched, and markedly prominent, forms a boundary- between the proximal sarcotheca and 
the internodium. 

The gonothecse are situate on the stem at the apoplnses. The young gonotheca shows distalh' 
a peculiar oblique termination, the one side of which gradually projects further forward, suggesting 
that the fully developed gonotheca would be furnished with a roof-like upper lip. Phylactogonia 
lacking. 



Material : 

"Ingolf St. 127 



66°33' N., 20°05' W., depth 44 fathoms, 5,6° 



Iceland: Tistil fjord, 66=43' N., i4°53' W., — 



78 - 





Ritchie (1912 p. 226) refers this species to Cladocarpiis\ but with a query, as he did not find 
gonangia in his specimens. These agree entirely with the present colonies (fig. XXXVI) which, from 
the comparatively short, broad hydrotheca;, can hardly be 
confused with other species from northern waters. The col- 
onies in question show that the species should be placed 
under Haliconiaria. The gonangia occur in several stages of 
development, but none full\- developed. The series of phases 
represented in the colonies investigated are entirely parallel 
to what we find in Cladocarpus integer ( G. O. Sars); the 
oldest stage also seems to show that it developes, as does 
the species mentioned, an "upper lip" which will dome out 

Fig XXXVI. Haliconiaria campaniclata from "In- 

more or less over the opening; further investigations must g^jp, gj ^^., Hydrothecate internodium from a 
determine, how far the development proceeds. hydrocladium in side and front %-iew. (x 60. 

Phvlactogonia are altogether lacking in the colonies here concerned, and the species must 
consequently be regarded as a Haliconiaria; there is, howe\er, the possibilit\- that it ma> later prove 
to be a primitive Cladocarpus. The otherwise close resemblance of the species to Cladocarpus integer 
would also seem to point in the same direction; the last-named species has hitherto likewise been 
regarded as a Halicornaria, but, as is further explained below, it is as a matter of fact a primitive 
Cladocarpus, whose phylactogonia do not alwa\-s or everywhere attain development. We cannot 
therefore altogether disregard the possibilit\- that Haliconiaria campanulata may also under normal 
conditions develope more or less regularly occurring phylactogonia. But as long as this has not been 
shown to be the case, the species must remain in the genus Halicornaria. 

Ritchie {1912 p. 227) could not state the locality of origin of the .species nearer than "from 
the neighbourhood of Iceland", which from a bio-geographical point of view is very meagre inform- 
ation indeed. The localities now recorded are the more surprising, since we should a prion suppose 



The Ingolf-Lixpediiion. \'. 7. 



_.. HYDROIDA II 



that we have to deal with a form from the warmer Atlantic regions; both the finds are in fact from 
near the north coast of Iceland. At the same time, however, it should be noted that both are situate 
in water of positive temperature; at the "IngolF St. 127 no less than 5,6^^ it is thus not impo.ssible 
that the occurrence of the species here is due to larval transportation from the Danmark Strait. Arctic 
the species certainly cannot be; even the one Aglaoplicniid hitherto found in any number in arctic 
water layers, Thecocarpus myriophylluin (Linne) is not indigenous there. We must therefore regard 
the Aglaopheniida on the whole as southern visitors in the colder northern seas. Halicornaria caiii- 
pamdata must likewise be placed in this category; its true home, however, has yet to be discovered. 



Nematocarpus nov. gen. 

Singh- or doubl\- pinnate colonies, the apophyses of the primary stem tubes bearing hydrocladia, 
which in fully developed colonies are secondarily branched. All sarcothecte immobile. The secondary 
hydrocladium is formed from the proximal sarcotheca branch on the primar\-, and stands in no relation 
to the gonangia. Tlie latter are not surrounded h\ any protective organs. 

This peculiar genus is known only in a single species, originally described as a Flalicoyiiaria 
h\ Allman (1874 p. 477). In Nutting's diagnosis of this genus (igoo p. 126) we find "Hydrocladia 
not branched; hydrocladial internodes without septa". The latter point is of minor importance even 
in distinction of species, but the first-mentioned character is also adopted by Stechow (1913 p. 43) 
"Hydrocladien einfach". 

On the other hand, we ma\- with some justification maintain that the genus Aglaoplwnopsis 
(Fewkes) is based on forms with branched hydrocladia. We must, however, here note a great differ- 
ence in comparison with Halicornaria raimilifcra Allman; the secondary branches in Aglaoplienopsts 
are hydrotheca-bearing plnlactogonia, and stand thus in definite relation to the gonangia; in this case, 
however, they have nothing to do with the gonangia, and do not develope into minor branches, as in 
Aglaophenopsis, Init into secondary Inxlrocladia of the same structure and appearance as the primar\'. 
This difference is important, inasmuch as we should, as Bale already (1887) pointed out, establish a 
new genus on the basis of the same. Tlie nearest related genera are Halicon/aria^ AglaopIiciiops/s\ 
and Cladocarptis, where we often, especially in the two last, find the sanre structure of the gonotheca 
as in the known Nrmatocarpiis species. 

Nematocarpus ramuliferus (Allman). 

1874 Halicornaria ramulifcra^ Allman, Report on the Hydroida Porcupine, p. 477, 13I. 67, fig. 3. 

1903 Halicornaria pluma, Brocli, Die von dem norwegischen Fischereidampfer "Michael Sars" ge- 

sanimelten Hydroiden, p. 8, Taf. IV, figs. 15—21. 

Doubly pinnate colonies, with somewhat irregularly branched, polysiphonic main stem. The 

primary tube is segmented, and has on the middle of each internodium a strong apophyse, directed 

alternately to each side, and a ])air of sarcothecse at the upper side of tlie apophvse; the sarcotheccE 

are adcaulinally split. F'rom the apophyse proceeds a Indrocladium, bearing a h\drotheca on each 



HYDROIDA II _- 



iiiternodiuni, surrounded by a pair of supracalycinc sarcothecte ou tlic distal part of the iuternodiuiu 
and an unpaired median proxiniall\-; between this and the base of the liydrotheca arises a sarcotheca- 
bearing liranch, which bends forward over the hydrotheca, and has on its convex (outer) side a row 
of sarcothecse. The sarcotheca-beariuo- branch of the basal liydrotheca developes into a secondary 
hydrocladium of the same appearance as the primar>-, but somewhat finer. Also in the exterior 
sarcothecal branches hydrothecae may be developed. The liydrothecse are fu.sed throughout tlieir 
basal half with the branch; the distal portion forms an angle with the basal, and widens some- 
what towards the aperture. The margin is furnished with 9 or 11 teeth; a large median proximal 
(abcladial), beside this as a rule a couple of smaller ones, tlien two well marked, and finally there are 
distally (adcladially) a pair of large teeth of the same size as the proximal, and between them a couple 
of quite small ones. 

The gonothecse are attached by a short, often almost rudimentary stalk to the stem; viewed 
laterally, the gonotheca is asymmetrically egg-shaped or o\al, with a distal lateral opening; seen from 
the front, the}- are oval, distalh- often broadly rounded; the aperture is round. At times there nia\ 
be some approach to formation of an "upper lip" above the mouth. 

Material: 

"Ingolf St. 44 6i°42' N., 9°36' W., depth 545 fathoms 4,8° 
- - 98 65=38' N., 26°27' W., - 138 - 5,9° 

The new colonies brought home by the "Ingolf show that the Halicomariii pliDiia Broch 
(1903 p. 8) described as distinct species is reallv only a somewdiat older stage of Xeviatocarpns raii/ii- 
liferus (Allman); we ha\'e now colonies showing the next stages through which they pass over to 
the possession of secondarily branched hydrocladia (fig. XXXVII a). Here also the species retains its 
peculiar nude posterior .side, whereas the front appears even more furry than in young colonies. There 
are certain signs which seem to indicate that a primary hydrocladium may bear several secondary 
ones. Haliconiaria phi ma was established chiefly on the strength of the fact that the basal sarcotheca- 
bearing branch of the hydrocladium has a hydrotheca, whereas the remaining sarcothecal branches 
lack hydrotliecEe. The present colonies now show that this was merely the forerunner of the second- 
ary hydrocladium, which gradually developes new hydrothecte with sarcotheca-bearing branches out- 
side the first'. At the same time, however, we find a hydrotheca with its corresponding sarcothecal 
branch developed at the second, often also at the third hydrotheca, and it is therefore highly possible 
that in still larger colonies we ma\' also here find developed secondary hydrocladia, showing that a 
primary hydrocladium can bear several secondar\- ones. 

The gonothecse are incompletely described both by Allman (1874 p. 477) and Broch (1903 
p. 8) probably from imperfectly developed specimens. They are of very peculiar form (fig. XXXVH b]. 
They are attached b>- a stalk which is not infrequently ver\- short, almost rudimentary. The one 
(adcauline) side is somew^hat flattened and short, the other however, highly curved and a good deal 
longer, so that the plane of the aperture is almost or entirel}- parallel with the longitudinal axis of 

1 In fig. XXXVII (7, the secondary hydrocladium .shows only one complete sarcothecal branch (the basal); this is 
due to the fact that the two next are broken off. Ordinarily, they appear in fully normal development at every^ single 
hydrotheca. 



76 



HYDROIDA II 





Fig. XXXVII. NematocarpJis ramuliferus. a basal part of a hydrocladiuin showing the development of the secondary hydro- 

cladium [/ primary, s secondary hydrocladium ; the proximal, sarcothecal branch is a little abnormally developed]. "Ingolf St. 

44. b internodium of the primary tube of the stem of a young colony from "Ingolf St. 98. c Hydrotheca, "Ingolf" St. 44. 

d Gonotheca in side view and front view. "Ingolf" St. 98. [a >' 45, b — 1/ X 90). 

the gonotheca it.self. The aperture is round or often somewhat broader, oval, and we thus find here 
a di.stinct approacli to the remarkable form of gonotheca which occnrs in all known forms of Aglao- 
/•/iriiopsis and Cladocarpus species, save that a distinct upper lip is less often clearly discernible. 

Xrinafocarpits nunulifrrMs was formerly only found in the cold area (fig. XXXVIII), but the 
two finds fall just in the zone where otherwise warmer atlantic, deeper-living visitors occur sporadi- 




ouom. looom. 

Fig. XXXVIII. Finds of X, matocarpna laimilifi iks. 



HYDROIDA 11 -- 



calh' ill the Norwegian Sea, and lie also comparatively near the snbmarinc ridges. It was therefore 
most likely that the species should be reckoned, bio-geographically, as belonging to the class of such 
visitors, and the two new finds appear to confirm this supposition, both being situate in the warmer 
atlantic region; one on the slope down towards the Atlantic Deep, west of the Faroe plateau, and the 
other on the east side of the threshold in Daninark Strait, where several other warm-water species 
also come in. The last-named locality, with a depth of 138 fathoms, is the shallowest of the finds 
made; the others lie deeper down in the true abyssal region. We are therefore justified in concluding 
that the species belongs to the warmer and deeper atlantic communities. 

Aglaophenopsis (Fewkes). 

Upright colonies with branched or unbranched main stem, the apophyses bearing unbranched 
Indrocladia with several hydrothecfe. All the sarcothecae are immobile. The gonothecse are protected 
by minor branches forming a basal appendi.x to the hydrocladia, and with both hydrothecse and sar- 
cothecas; the gonothecse are situate on the stem or on the minor branches. 

Practically speaking, this definition coincides with Nutting's limitation of the genus (1900 
p. 118). Nutting also lays most stress upon the occurrence of the protective branchlets, but does 
not seem quite to have realised that the principal character for these lies in the fact that they bear 
lu'drotheca', not, as in the case of Chidocar/'Kx^ sarcothecce only. Aglaopliciiopsis differs from Xniia/o- 
carpHs in principle b\- the fact that the minor branches do not develope into secondary hydrocladia of 
normal appearance, but merely appear as protecti\'e appendices in fertile colonies. 

Aglaoplioiopsis-Cladoccnpus form a pair of genera parallel with Thrcoiarpiis-Aglaophenia. As 
a matter of fact, we cannot determine which of the two in each case is the more primitive; having 
regard, however, to the development of a species such as Nematocarptis raniiilijeriis^ which appears to 
be more primitive than the others in the state of its gonangia, we must probably incline to the theory 
that CladocarpHs and .iglaopluiiia are the more primitive, rather than the more highly developed. 
Still, we can hardly in either case regard the one genus as derived from the other; it would seem 
more likely that each has arisen independently. 

Aglaophenopsis COrnuta (Verrill) Nutting. 
1879 Cladocarpns corinitns, Verrill, Notice on recent additions to the marine fauna, p. 310. 
1900 Aglaopliciiopsis coniufa. Nutting, Plumularid;e, p. 120, pi. 30, figs. 6—9. 

Colonies doubly pinnate, with branched polysiphonic main stem, monosiphonic in its extreme 
portions. The priinar>- stem tube is divided into short internodia, bearing in the middle an apophyse 
directed obliqueh- forward and sideways, and three sarcothecEe, one pair nearest the upper side of the 
apophyse, and an unpaired one medially on the lower part of the iuternodium; all are split along the 
upper side, and project far forward, especialh' the paired ones. At the base of the apophyse, between 
it and the unpaired sarcotheca, there appears a pattern which must be interpreted as an abortive 
hydrotheca. The hydrocladia have on the rear side a markedly prominent keel; they are divided into 
short internodia, each bearing a large hvdrotheca and three sarcothecas, a supracalycine pair at the 



78 



HYDROIDA II 



opening, and a median proximal sarcotheca, the opening margin of which hardly reaches up to the 
middle of the hydrotheca; the sarcothecse have a dentate margin, and project far forward; they are 
adcanlinally split. The Iiydrotheca is laterally compressed; seen from the side, it is egg-shaped and 
pointed at the lower end. The hydrotheca has abcaulinally a median keel, running out into a large, 
hollow, generally sharply horn-shaped tooth, the free projecting part of which may reach a length of 

up to ^'. that of the h^'drotheca; the cavity forms a continuation of 
the lumen of the hydrotheca. The hydrotheca margin has at the 
base of the mentioned projection a median abcauline tooth, and 
on either side four teeth, which become broader and less pro- 
nounced nearer the hydrocladium. The internodium has four to six 
inner ribs at the hydrotheca wall; an inner rib also bounds the 
lumen of the proximal sarcotheca on its lower end. The hydrotheca 
lacks inner ribs or septa. 

The gonothecfe are set on the stem, or more often on short, 
once dichotomicall)- divided branchlets proceeding from the basal 
internodium of the hydrocladium beside its proximal sarcotheca ; the 




Fig. XXXIX. Aglaophenopsis cornuta. 
"Ingolf St. 25. — a. Caiiline interno- 
dium of the primary tube, showing 
both sarcothecae of the upper pair. — 
b. Front view of the internode, showintr 



the abortive hydrotheca at the base 

of the apophyse above the proximal small branches bear as a rule a hydrotheca on each branchlet ; more 

sarcotheca. (X 40I. , , , , i ,, .1 .1 tm 

rarel\- the one may ha\-e two hydrothecte, the other one. 1 he gono- 
theca is broad oval to pear-shaped; seen from the side it is somewhat more slender, with subterminal 
opening on the adcladial side and with a short upjjer lip, formed b>' the abcladial wall, which is 
domed forward roofwise over the opening. 
Material : 

"Ingolf" St. 15, 66°iS' N., 25°59' W., depth 330 fathoms ^0,75^ 
- - 25, ■ 63>' N., 54°2,s' W., - 582 - 3,3° 

98, 65°38' N., 26°27' W., - 138 - 5,9° 



100 



(without further details) 



Greenland: Davis Strait, 

65°3o' N-, 55°36' W., - 289 - 

In Nutting's description of jlghiop/iriiopsis cornuta (1900 p. 120) there is a misunderstanding 
as to the cauline sarcothec;c, which he describes as follows: "cauline nematophores very large, one 
just at the base of each lu'drocladium, another immediatel\- below this, and a third, long and spur- 
like opposite the base of each hydrocladium". As regards the last sarcotheca (fig. XXXIX ff) this is 
as a matter of fact one of a i)air situate nearer the upper side of the base of the apophyse; both of 
them project far out from the stem, but on viewing the colony from the front (fig. XXXIX b) the one 
is hidden by the basal part of the hydrocladium. The lower, proximal sarcotheca is ver>- broad, and 
does not project quite as much. The .sarcotheca which Nutting mentions as just at the base of the 
hydrocladium, i. e. practicalh- on the apophyse itself, must on the other hand be regarded as an abort- 
ive hydrotheca wliich has been checked in its development b_\- the growth of the apophyse and Indro- 
cladium; it bears no resemblance to the remaining sarcothecoe, and does not .seem to be provided with 
any sarcostyle or nematophore. A point of great importance in this explanation is also the fact that 
the basal portion of large pinnate parts ma)- be formed of internodia with Indrotheca?, but without 



HVDROIDA 11 



79 



apophyses and h\drocladia; here again we find the supracalycine sarcothecie particularly well devel- 
oped, in the same manner as o\-er the apophyse, and more than on the normal cladial internodia; at 
the same time there is not the slightest indication of an\^ such jjattern as that which Nutting has 
taken for a sarcotheca. The abortive hydrotheca probably forms a parallel to the apophysal "mamelon" 
in Nrmcrtcsia and Polyiicmertcsia^ and would seem to throw some light on its origin. 

There is considerable variation in the appearance of the hydrothecte (fig. XL) especially owing 
to the fact that the abcauline keel and its prolongation vary \ery greatly both in length and breadth; 
the outgrowth may be broad and blunt, or more slender, and running out to a ])oint. It forms an 
incurvation in the wall of the hydrotheca; at its ba.se, the hydrotheca is furnished with a sharply cut 
tooth, directed obIiquel\' inward and forward, and between this and the internodium the edge shows 



; 






Fig. XL. Aglaoplicnopsis cornuta, a Basal part of a hydroclailium with the phylactogoniuni and a 

gonotheca in side view from "Ingolf" St. 98 (X 40). — h Front view of a hydrotheca from the 

same colony ( X 60). — c Side view of a hydrotheca from the same colony I X 60). — J H3'dro- 

theca from a colony from "Ingolf" St. 25, side view ( X 601. 

as a rule four teeth on either side, which become broader and lower nearer the Indrocladium. Tlie 
innermost tooth on either side, and at times the one next to it, can e\-en now and again be entirely 
effaced, so that only two abcauline teeth can be distinguished on either side. — The proximal sarco- 
theca also varies considerably, diverging now more, now less wideh' from the hydrotheca, and having 
a free portion of varying length. 

The basal internodium of the hydrocladium has a different structure owing to the position of its 
proximal sarcotheca. This is shifted to the obliquely upward trending hydrocladium, — the side away from 
the stem — and is also somewhat smaller than on the following internodia. The cause of this must 
be sought in the growth of the phylactogonium. 

The phylactogonium (fig. XL ff) is segmented and has only hydrothecae on two of its branches; 
on one of them at times two, but as a rule onlv one on each; thev are surrounded bv the usual three 



8o 



HYDROIDA H 




zoo rn. 6 CO m. looom. 2000 m. 

Fig. XLI. Finds of Ag/aopkenopsis cornuta in the Northern Atlantic. 

sarcothecas, which, however, are here generally somewhat smaller than on the hydrocladia. The gono- 
theca has a well developed npper lip, which does not appear clearly from Nutting's illustration and 
description. It is domed strongly forward, .so that the aperture becomes turned down towards the base. 
Aglaophenopsis corintta is a t\pical deep-sea species which has only in Davis Strait been 
observed at loo, and in Danmark Strait at 138 fathoms depth; it can thus also penetrate up into the 
lower part of the littoral region. The species probably belongs stricth- speaking to the warm, deep 
northern part of the Atlantic; it moves up into Davis vStrait, where it appears to be of not infrequent 
occurrence (fig. XLIi and has now, as we see, also been recorded from Danmark Strait. As it is not 
known from other localities than those mentioned and the waters off Nova Scotia, we are justified 
in characterising it for the present as a west atlantic species. 



Aglaophenopsis (?) pharetra n. sp. 
The colony pinnate with polysiphonic stem, monosiphonic in the extreme portions, and having 
the primary tube indistinctly segmented. Each of the internodia of the stem bears at two thirds 
of its height a well defined, fairly short apopluse, and three unpaired sarcothecte, two in the median 
line below the apophyse, and the third in the corner between the stem and the apophyse above the 
origin of the latter. The alternately placed hydrocladia form almost a right angle with the stem; 
they are divided into long internodia, each of which bears a hvdrotheca, and three sarcothecpe, a 
supracalycinc pair at the opening of the hydrotheca and an unpaired proximal about midway between 
the base of the hydrotheca and the proximal end of the internodium; the opening margin of the 



HYDROIDA 11 



8i 



proximal sarcotheca does not reacli up to the base of the hydrotheca; all the sarcothecse have a smooth 
margin and are adcanlinalh- split. The length of the hydrotheca is about three-fifths that of the inter- 
nodium. The hydrotheca is of extremely slender build, not laterally compressed, somewhat expanded 
towards the opening; the opening margin is quite smooth. Numerous .small inner ribs are found in 
the internodia along the hydrotheca wall; a rib also forms the lower boundary of the proximal 
sarcotheca. 

Material: 

"Ingolf St. 8i 6i°44' N., zfod W., depth 485 fathoms, 6,1°. 




hJ 



r\ 



fA 



Of this remarkable species we have only a 
single quite small colony, the height of which amounts 
to onl\- about 2 cm. above the close rootlike net- 
work by which it was attached. The upper 6 mm. 
bear the Indnicladia, two fairly long on each side, 
and there is also, at the top of the colony on the 
left side, a third hydrocladium where the hydrotheca 
no 2 is still only indicated. On the lower part of 
the stem there is a secondary tube, which creeps 
upward along the lower 7 mm. of the primary, show- 
ing that the fully grown colony will exhibit a poly- 
siphonic stem. The primary tube differs from that 
of most other species in tlie arrangement of the sar- 
cothecse (fig. XLII o): paired canline sarcothecfe are 
lacking, but each internodium has three unpaired 
sarcothecse; the two lower in the median line one 
above the other, and the third in the corner at the 
upper side of the apophyse. 

The hydrotheca; are very characteristic (fig. 
XLII b, r), in appearance not unlike a slender quiver, whence the species has been named pharctra. The 
opening margin is quite smooth, without indication of teeth or irregularities. The supracalycine sar- 
cothecse project somewhat up beyond the hydrotheca opening. The proximal sarcotheca is separated 
by a quite considerable interval from the hydrotheca. 

As no indications of gonangia have yet been found, the s\'stemat!C position of the species 
cannot yet be determined with certainty. It presents, however, a so considerable resemblance to 
Aglaophotopsis VerriUi Nutting that it should, for the present at any rate, be placed near tiiis; the 
differences consist in the somewhat shorter and broader hydrothecse of the latter species, where the 
opening is furnished with teeth, as also in the much shorter distance from the hydrotheca to the 
proximal sarcotheca. The species is tlierefore placed with a query in the same genus, under the name 
of Aglaophenopsis (f) pharetra. On the other hand, it also resembles not a little certain Ckidocarpzis 

The Ingolf-Expcdition. V. 7. ' 



Fig. XLII. Aglaoph.nopsis (?) pharetra from "Ingolf St. Si. 

a. Internodium of the primary cauline tube with the apophyse. 

b. Internodium of tlie hydrocladium with hydrotheca in side 
view. c. Frontal view of hydrotheca and internodium. (^XSo). 



82 



HYDROIDA II 



species such as Cladocarpus tenuis Clarke and Cladocarpiis flexiwsns Nutting. There is therefore the 
possibiHty that the species may liave to be referred to this genus, and the query affixed to the generic 
name must remain for the present. 

Onl)- the one specimen was found, in the deep south west of Iceland. The locality suggests 
that we have here to deal with a warm-water form from the deep water of the Atlantic. 



Cladocarpus Allman 

Upright colonies with branched or unbranched main stem, the apophyses with unbranched 
hjdrocladia with several hydrothecse. All the sarcothecse are immobile. The gonothecse are protected 
by small branches, phylactogonia, which form a basal appendix to the hydrocladia, and are furnished 
with sarcothecse, but lack hydrothecte. The gonothecte are set on the stem or on the phylactogonia. 

Cladocarpus integer (G. O. Sars). 
1874 Aglaophenia iniegra, G. O. Sars, Bidrag til Kundskaben om Norges Hydroider, p. 100, pi. 2, figs 

II— 15. 
1879 Cladocarpus Pourtalesi. Verrill, Notice on recent additions to the marine fauna, p. 309. 
1893 Cladocarpus Holnn] Levinsen, Meduser, Ctenophorer og Hydroider, p, 67, tab. VIII, figs. 15—18. 

The colonies are doubly pinnate with branched polysiphonic main stem, exhibiting only in its 
very outermost parts the primary segmented tube alone; this has fairly short internodia, bearing on 
the basal third a strong but short apophyse; the internodium is also furnished with three adcaulinally 
split sarcothecse, an unpaired median at the bottom, and a pair at the upper side of the apophyse. 
The internodium of the hydrocladium has a fairly large Indrotheca and three sarcothecse, a supra- 
calycine pair at the opening, and a median proximal sarcotheca, which with its opening margin hardly 
reaches up to the basal fourth of the hydrotheca; all the sarcothecae approach the tubulous form, but 
are adcladially split. The hydrothecse are laterally somewhat compressed, and slightly expanded at 
the opening; the oj:)ening margin, in the hydrothecse as in the sarcothecse, is quite smooth. The inter- 
nodium exhibits one or two inner ribs at the hydrotheca wall, and two below the proximal sarcotheca. 

The gonothecce are fastened as a rule by a rudimentary stalk to the stem or to the phylac- 
togonia, which are almost invariably unbranched, and have tvvo irregular rows of sarcothecce; the 
phylactogonium proceeds from the basal internodium of the hydrocladium, beside the proximal sarco- 
theca. The gonotheca is somewhat flattened; seen from the flat side it is broadly pear-shaped, broadl)' 
rounded distally; viewed laterall}-, it is a slender oval, with a distal lateral adcauline opening over 
which the abcauline wall domes out like an upper lip. 

Material : 

"Ingolf" vSt. 25 63°3o' N., 54°25' W., depth 582 fathoms, 3,3° 

- - 27 64°54' N., 55°io' W., - 393 - 3,8° 

- - 94 64°56' N., 36°i9' W., - 204 - 4,1° 

- - 98 65°38' N., 26°27' W., - 138 - 5,9° 



HYDROIDA II 



83 



Greenland: Davis Strait, depth 80 fathoms (without further details) |type specimen of Clado- 

carpus Holmi\ ' 
Iceland: 5 miles E. of Seydisfjord, dcptli 135 fathoms (labelled Cladocarpiis IIolmi\. 

Cladocarpus iiitrgcr has led a somewhat unsettled existence in various genera. G. O. Sars 
(1874 p. 100) regarded it as an Aglaopliciiin^ and is followed by Bonne vie (1899 p. 93) who places 
all northern Aglaop/ieiiiida- in this one genus. Jiiderholm (1909 p. 109 and no) refers to it either 
as Halicoruaria iutcgra or as Cladocarpus Iloliiii and Cladocarpus Pourialcsi^ while Ritchie (1912 p. 
228) classes the species under Halicoruaria. A very rich material from the Trondhjem l-jord, where 
the species is found in great numbers, enabled me to study it further, and determine its systematic 
jjosition. And it now turns out that the species must be regarded as a jjrimitive Cladocarpus. The 



^ 





Fig. XLIII. Cladocarpus integer, 
a. Basal parts of a liydrocladium and its phylactogonium with an entire 
gonotheca, from the Trondhjem fjord (X 40). — *. Hydrotheca of the 
same colony (X 60). — c. Hydrotheca of a colony from "Ingolf vSt. gS 

(>; 60). 

gonothecae are very often fixed to the stem or more correctly, to the apophyses; Ritchie's descrip- 
tions show that this may often occur on the whole for an entire colon\-, and that the phylactogonia 
may in consequence be altogether lacking, which is also exceptionally found to be the case in some 
of the colonies from Trondhjem Fjord. The great majorit}- of the colonies have, however, at any rate 
in considerable parts of each, developed primitive but typical phylactogonia (fig. XLIII a). These pro- 
ceed from the basal internodium of the hydrocladium beside the proximal sarcotheca. The phylacto- 
gonia are practically always unbranched, and furnished with two somewhat onesidedly arranged rows 
of sarcothecse, set either in pairs or irregularly placed; only once or twice have I found phylactogonia 
which had, by dichotomic division, developed a short lateral branch of the same structure. The phylac- 
togonium also exhibits irregular segmentation. It has as a rule two or three gonotheca; on the same 
side as the sarcothecse. The gonotheca is of the typical Cladocarpus form, with upper lip; this is, 
however, shorter than in most other species, so the opening is not yet directed downwards. 

Ritchie's specimen (1912 p. 228) should, it woidd seem, be taken as the representative of a 
special variety Ritcliici nov. differing from the t\pical form in having the hydrotheca margin slightly 



84 



HYDROIDA II 



sinuous. The internodial ribs of this variety are also somewhat more strongly marked than in the 
common form, and it likewise shows a more pronounced indication of intrathecal septum. 

The features mentioned, that the species can at times lack phylactogonia, show that Clado- 
carptis Fourtalesi must be considered as a synonym. The difference between this species and Clado- 
carpus Holmi\% not apparent from Levinsen's description of the latter (1893 p. 67) and an investig- 
ation of the type specimens shows that the species has been founded on typical colonies of Clado- 
carpus integer. 




ZCQO rrt. 



1m<;- XI, IV. The distribution of Cladocarpus integer in the northern .Atlantic. 
In the hatched re<rions the Hterature denote.s a scattered occurrence. 



The species is a typical warm atlantic form, which appears to have its chief occurrence in the 
western Atlantic, in the lower part of the littoral region and the upper part of the abyssal. In northern 
waters, it has long been known from the west coast of Norway, and is also found to be a not alto- 
gether infrequent visitor to Greenland, both in Davis Strait and up towards Danmark Strait (fig. XLIV). 
On one occasion, it was met with off the east coast of Iceland, at the boundary of the arctic deep 
region. Tliat il lias not yet l)een located with certainty between the British Isles and Iceland must 
be due to accident. Ritchie (1912 p. 228) had before him a specimen brought home by Hull trawlers, 
and we may doubtless presume that it would then have originated from the northern slope of the 
North Sea plateau or from the Faroe Islands Banks. 



HYDROIDA II 



85 



Cladocarpus formosus All man. 

1874 Cladocarpus formosus^ Alluian, Report on the Hydroida Porcupine, p. 478, pi. 68, fig. i. 

1893 Cladocarpus crci/ulafus, Levin.sen, Medu-ser, Ctenophorer og Hydroider, p. 68, pi. VIII, fig.s. 13 — 14. 
The colonies liave an unbranched or branched polysiphonic stem. The primary, foremost tube 
is divided into short internodia with a short apophyse directed obliquely forward and sideways, and 
three sarcothecse, a pair at tlie ujjper side of the apophyse, and an unpaired median on the basal 
part of the internodium, all adcladially split. The internodia of the hydrocladium are short, and bear 
a large broad hydrotheca and three sarcotheca:, a supracalycine pair at the hydrothecal aperture, and 






Fig. XL\^ Cladocaiptis forinoms. 

n Basal part of a hj-drocladium with its phylactogonium, "Iiigolf' St. 29 (X 40). 

b Hydrotheca of the same specimen (X 60). 

c Hydrotheca of the variety from -'Ingolf' St. 25 in side view (X 6o)- 

d Front view of a hydrotheca of the same specimen 1 X 601. 

a median proximal, which reaches with its opening margin nearl\- up to the middle of the hxdrotheca; 
the sarcotheca; have a slightly dentate margin, and are adcaulinally split. On the basal mteruodunn 
of the hydrocladium, the pro.ximal sarcotheca is divided off by an interval from the hydrotheca. The 
hydrotheca; are large, and nearly circular in transverse section, with an abcladial intrathecal septum; 
the opening margin is slightly sinuous, with more prominent teeth abcladialh', and with a quite di- 
stinct abcladial median tooth. 

The gonothec£E are situate on the stem or on the phylactogonia, which proceed from the basal 
internodium of the hydrocladium, at the interval between the hydrotheca and the proximal sarcotheca. 
The phylactogonia have, after two dichotomic divisions, three branches, and bear on their outer side 
two rows of paired or irregularly placed sarcotheca;. The gonothec^ are somewhat flattened, pear- 
shaped from the broad side, with transverseh- rounded distal part; seen from the side, with a termmal 
lateral opening over which one wall domes out in a markedly prominent upper hp. 



36 



HYDROIDA II 



Material: 

"Ingolf St. 25 63=30' N., 54°25' W., depth 582 fathoms 3,3° 

- - 29 65°34' N., 54°3i' W, - 68 - 0,2° 

- - 34 65=17' N, 54°i7' W., - 55 - 

- - 93 64=24' N, 35°i4' W., - 767 - i'46" 

- - 97 65=28' N., 27°39' W, - 450 - 5,5° 

- - 127 66=33' N., 20=05' W., - 44 - 5,6° 

Greenland: Davis Strait, depth 80 fathoms (without further details) [type specimen of Clado- 

carpiis crenidahis\ 
65=39' N., 28=25' W., depth 553 fathoms [type specimen of Cladocarpus crciiulafits]. 

CladocarpHs formosus is described in detail by Ritchie (1909) from some colonies taken at 
about the same place as A 11 man's type specimens. Among the features which he here notes is 
the fact that the opening margin of the sarcothecse is "serrate". Most of the present colonies fully 
agree with Ritchie's careful description. We have, however, from the "Ingolf St. 25, in addition 
to many typical colonies, also some few of slightly different structure (fig. XLV). The hydrothecse 
are here somewhat broader than the normal, the septum is set a little deeper down, and goes consider- 
ably farther in towards the adcladial side than in ordinary colonies of the species, while on the other 
hand the internodial aibs are less pronounced, and fewer in number. Furthermore, all the sarcothecse 
here have smooth opening margin. The points of difference, as compared with the typical form of 
Cladocarpus /orinosits, ■a.it thus sufficiently marked; they are however, too slight to warrant our mark- 
ing off a distinct .species, since no other differences can be discerned. The colonies should thus merely 
be regarded as representatives of a special variety within the species. 

Ritchie (1909 p. 314) points out that Levin sen's Cladocarpus crenulatus (1893 p. 68) must 
be regarded as a synonym of Cladocarpus foriiiosiis\ and after having examined Levinsen's type 
specimen.s, I must entirely concur in this view. Bonne vie (1899 p. 95) mentions Aglaophenia /or?nosa 
from a station near Spitzbergen; her description however, differs not a little from Allman's, and 
from those of later writers; in the first place, no mention is made of the intrathecal septum, in addi- 
tion to whicli, tlie description of tlie hydrotheca as "almost cylindrical, regularly dentated round the 
margin" is hardly in accordance with what we otherwise know of the species; the published drawings 
(1898 Taf. 2, fig. 3) also differ somewhat, so that the identity of the colony seems doubtful. An investi- 
gation of the type specimen, however, shows that the intrathecal septum is present, and that the spe- 
cimen only differs from the colonies here in question in the somewhat more distinct and regular den- 
tition of the hydrotheca margin. In addition, one of the phylactogonia is pinnately branched, as in 
Cladocarpus paradiseus AUman, while the others are dichotomically branched. 

Cladocarpus formosus is plainly one of the most common forms in the warmer tracts belonging 
to the upper part of the abyssal region in the North Atlantic (fig. XLVI) and penetrates thence up 
into the lower part of the littoral region. It is originally known from the southernmost part of the 
cold area, wheix the latter runs into the Faroe Channel, but .should here be regarded as a visitor, 
brought in by larval transport with the Atlantic current. The species is previously known from 



HVDROIDA II 



87 



Davis Strait, from where the "Ingolf brought back several colonies, and has now also been found in 
deeper water right up in the Danmark Strait. From here again, it may be transported into the waters 
along the north coast of Iceland, as shown by the find at the "Ingolf St. 127, where the species 
occurs together with Halicornaria campanulata. 




200 m. c-_--- 600 m. .»._._.«..„iooom. 

Fig. XLVI. Finds of ClnJocarpiis fo>mosi<s in the Nortliern Atlantic. 



Cladocarpus Diana nov. sp. 
The colonies are singly pinnate with polysiphonic, in the upper parts monosiphonic main stem, 
which is not particularh- strongly pronounced. The primary tube is indistinctly segmented, with long 
interuodia, each having on its upper third an apophyse turned almost straight out to the side, alter- 
nately directed to either side of the stem. The internodium further has three or four sarcothecae, a 
pair at the upper side of the apophyse, and one or two unpaired in the median line on the lower part 
of the internodium ; all are adcaulinally split. The interuodia of the hydrocladium have a large hydro- 
theca and three sarcothecte, a supracalycine pair at the h\drotheca aperture, and an unpaired median 
proximal sarcotheca which reaches with its opening margin barely a little beyond the bottom of the 
hydrotheca. The supracalycine sarcothecse approach the tubulous form, but are adcladially split; the 
proximal is of very typical shape, being much widened out laterally towards the opening, so that the 
latter is seen to be as broad as, or even slightly broader than, the lower part of the hydrotheca; the 
free adthecal wall has disappeared; the margin is slightly dentate. The hydrothectc are large, some- 
what compressed lateralh', with expanded opening part; the margin of the aperture is armed with 9 
strong teeth, an abcladial median, and between this and the internodium four on cither side. There 



88 



HYDROIDA II 



is an indication of four to five faint inner ribs in the internodium at the h>drotheca; the proximal 
sarcotheca is bounded on the lower side by a strong rib. 

The gonothecre are situated on dichotomically branched phylactogonia proceeding from the 
basal internodium of the Indrocladia beside its proximal sarcotheca. The phylactogonia have three 
branches, which bear, on the side turned towards the stem, a row of sarcothecae, and can be indistinctly 
segmented. The gonotheca is somewhat flattened; seen from the broader side it is a broad oval, or 
egg-shaped, fastened by the pointed end to the phylactogonium. The opening is broad, subterminal, 
and turned downwards owing to the fact that the abcladial side curves far out beyond the opening 
as a broad upper lip. 






Fig. XLVII. Cladocorpiis Diana, "higolf St. 78. — a Phylactogonium with gonotheca (X 40). 
/: HvdroUieca in side view (X 60). — c Hydrotheca in front view (X 60). 



Material : 



"Ingolf" vSt. 46, 6i°32' N., ii°36' W., depth 720 fathoms 2,4° 
- - 78. 6o°37' N., 27°52' W., - 799 - 4,5° 

Cladocarpus J>iaiia has much stronger hydrothecal teeth (fig. XLVII) than most other species 
of the genus; nearest in this respect is Cladocarpus compressits Fewkes, but the teeth there are some- 
wlial broader; in addition, the intervals between the teeth in Cladocarpus Diana are curved somewhat 
outwards. The most remarkable character, however, lies in the proximal sarcotheca. Seen from the 
side, this does not differ greatly from other previously known species, being onh- unusually short, so 
that the opening margin does not extend much beyond the bottom of the hydrotheca. But on exam- 
ining the sarcotheca from the ventral side (fig. XLVII c] we find that it has its greatest breadth at 
the opening margin, which may even be slightly longer than the breadth of the lower and middle 
part of the hydrotheca. The sarcotheca has only one opening, which is correspondingly larger, the 
free wall turning towards the hydrotheca being entirely effaced. 



HYDRUIDA II 



89 



Cladocarpits Diana exhibits also certain peculiarities in the j^'onosoine (fig. XLVII c/). The phyl- 
actogonium divides dichotoniicalh- a little abo\e the base, and the outer branch, that farthest from 
the median line of the colony, soon divides again dichotomically into two. giving a slightly u])\vard 
curving ph\'lactogonium with three short branches. These have onl)- a single open row of strong 
sarcothecse on the side turned towards the median plane of the colony; each branch has from three 
to five sarcothec:e. The branches of the pli\lactogonium are richly furnished with inner ribs, and are 
also often irregularh- segmented. The phylactogonia bear two or three gonotheca; of the same type 
as that usual in the genus, with a strongly developed upper lip domed out roofwnse over the broad 
opening, which is turned towards the phylactogonium. 

The colony from the "Ingolf" St. 46 exhibits the peculiarit\- of having the outer branch of the 
seventh phylactogonium from below on the left side prolonged; at the terminal point of the normal 
branch arises a further lateral branch; the outer branch is further prolonged, and has, outside the 
abo\'e-mentioned supernumerary branch, three hydrotheca;, and thus from here presents the appearance 
of a hydrocladium, which in addition to its ba.sal hydrotheca further shows the incipient develop- 
ment of a secondar\ phylactogonium. The entire formation nuist be regarded as an abnormity. 



Cladocarpus bicuspis (G. O. Sars) Jaderholm. 

1874 Aglaopheiiia biaispis, G. O. Sars, Bidrag til Kundskaben om Norges H)droider, p. 9.S, pi. 2, figs. 7—10. 
1909 Cladocarpus bicuspis^ Jaderholm, Northern and Arctic Invertebrates, p. no. 

The colony is pinnate with polysiphonic, in the outer portions monosiphonic nuiin stem. The 
primary tube is divided into short mternodia, each bearing an apophyse directed obliquely forward 
and sideways, turned alternately to either side of the median line. The internodinm is further provided 
with three sarcothecii;, a pair at the upper side of the apophyse, and an unpaired one in the median 
Hue of the internodinm, close below the apophyse; all are adcaulinally .split. The internodia of the 
hydrocladium have a ver\- large hydrotheca and three sarcothecie. a supracalycine pair at the h>dro- 
theca aperture and an unpaired median proximal reaching up to the lower third of the hydrotheca; 
all sarcothecse are adcladially split, and have quite smooth margins. The hydrotheca; are laterally 
much compres.sed, with outward curving opening margin, and with an abcauline pair of large teeth; 
the nuu-giu otherwise smooth ; the sinus between the teeth is almost square. The teeth are concave, 
the incurvation strongest at the median line. From the sinus between the teeth an inner rib runs 
along the abcladial side of the h\'drotheca to its middle, where it terminates in a strong S-shaped 
intrathecal septum, dividing the h_\drotheca into a larger upper portion and smaller basal part, the 
latter half the size of the former. The internodium is furni.shed at the hydrotheca wall with four or 
five short ribs, the proximal sarcotheca is bounded on the lower side by a an oblique .septum. 

The gonotheca; are situate on the stem or on short, dichotomically tluee- to four-branched 
ph\lactogonia, proceeding from the basal internodium of the hydrocladium beside its proximal sarco- 
theca. The phylactogonia are furnished with' sarcothecse irregularh- arranged, and not infrequently 
having indistinct segmentation. The gonotheca is somewhat flattened; from the broad side it is reversely 

12 

'I lie Iiigolf-Expedition. V. 7. 



go 



HYDROIDA II 



conical, broadly rounded distally, ^vith a broad opening; towards the phylactogoniun, ; in lateral view, 
the abcladial wall is seen to dome out in a large upper lip over the opening, which is consequently 
turned downwards towards the base. 

Material: 

"Ingolf" vSt. 51 64°i5' N., i4°22' W., depth 68 fathoms 7,32° 
- - 98 65°38' N.. 26°27' W., - 138 - 5,9° 

Of this highly peculiar species, a couple of well developed colonies have been found; it re- 
sembles somewhat Cladocarpiis paradisms Allman, with its two strong abcladial teeth, but these are 






Fig. XLVin. Cladocarpui bictispis from "Iiigolf" Ht. gS. 

n Basal part of a hydrocladium with its phylactogoniuni (X 4°). 

* Side view of a hydrotheca (X 60). -- c Front view of a hydrotheca (X 60). 

more strongly developed in Cladocarpus hicuspis (fig. XLVIII) than in the species mentioned, and 
their appearance is the more striking from their marked incurvation, which renders the median sinus 
more prominent. The strong S-shaped septum is suggestive of Cladocarpus sigiiia AUmann; on the 
other hand, the inner longitudinal abcladial keel seems to be without parallel in the genus. 

The phylactogonia are dichotomically branched, the ramification does not alwa\s take place 
once only, as in the one shown (fig. XLVIII a\ but as a rule two or three times, so that we have 
three or four terminal branches. The gonothecce shown by G. O. Sars (1874 pi. 2, fig. 8) are not yet 
fully grown. The full-grown gouotheca presents the same typical appearance as the remaining north- 
ern Cladocarpus species, with a much more strongly developed upper lip domed out over the open- 
ing; it is here as strongly developed as in Cladocarpus Diana. 

Cladocarpus bicuspis is altogether a rare species in the regions investigated (fig. XLIX) and as 
it does not seem to have been found at all elsewhere, its true habitat is still a matter of doubt. In 
the northern waters, the species belongs to the typical visitors from the warmer atlantic waters, 
being previously known only from between Stavanger and Trondhjem Fjord on the west coast of 



HYDROIDA II 



91 



Norway; now the "Ingolf lias added two new localities, the one being off the south-east point of 
Iceland, the other in the eastern part of Danniark Strait, at a spot where several representatives of 
the heat-loving deep-water fauna of the Atlantic have been found. The bathymetrical position of the 
species is also somewhat doubtful: up to the present it has only been found in the middle and 
lower parts of the littoral region. 




. _» ioom. 



Fig. XLIX. The occurrence of Cladocarpus bkuspis in the Northern Atlantic. 
In the hatched region the literature notes a scattered occurrence. 



Gen. Thecocarpus Nutting. 

Upright colonies with branched or unbranched main stem, the apoph)-ses bearing unbranched 
hydrocladia with several hydrotheca;. All sarcothecse immobile. The gonotheca: are set in a corbula 
formed by a metamorphosed hydrocladium; the blades of the corbula, or ribs, have each a hydrotheca 
near its point of origin. 

Nutting (1900 p. 106) attaches primary importance to the question whether the stem is mono- 

siphonic, a character which, even in distinction of species, is of subordinate weight; a species such as 

Thecocarpus myriopliyllum (Linne) occurs in northern seas not infrequently fertile with monosiphomc 

stem, while other colonies have a polysiphonic basal part; but it is really only in southern waters 

that strong colonies of this species are found with polysiphonic stems, at an>- rate a couple of feet 

hicrh. This feature, then, is of little or no interest from the point of view of generic distinction; on 
'' 12* 



Q2 HYDROIDA II 



the other hand, it is perfectly correct to take the hirnishnient of the corbnla blades with hydrothecte 
as of primary importance, which Billard (1913 p. 85) also points out. The breadth of the single cor- 
bnla blade however, is of minor significance in this respect, and cannot be taken as proof that the 
corbtila here is more primitive than in Aglaopheuia, where narrowbladed corbnke have also been found. 



Thecocarpus myriophyllum (Linne) Nutting. 

1758 SertularLa myriopliyUuiii^ Linne, S>stema naturae, ed. 10, p. 810. 

1900 Thecocarpus viyriop/iylluvi, Nutting, Plumularidse, p. 107, pi. 24, figs. 12 — 13. 

The colonies have an unbranched or branched, poly*iphonic or monosiphonic main stem. The 
primary tube of the stem is divided into shorter or longer internodia, each bearing about the middle 
a short apophyse, directed obliquely forward and sideways; at the base of this at its upper side there 
is a pair of sarcothecse, and on the basal part of the internodium an unpaired median sarcotheca. The 
.short internodia of the hydrocladinm have each a large ludrotheca, slightly compressed laterally, and 
three sarcothecse, a supra-calycine pair at the hydrotheca opening and a short pro.ximal unpaired sar- 
cotheca, the opening margin of which does not reach up to the middle of the hydrotheca; all sarco- 
thecse are adcaulinally split. The hydrotheca margin is furnished with a strong, sharply cut median 
abcauline tooth; between this and the hydrocladinm the margin is slightly dentate or curved, more 
faintly near the hydrocladinm than farther from it. The opening margin stands almost perpendicular 
to the hydrocladium. 

The gonothecse proceed from a hydrocladium which is transformed into a narrow-bladed cor- 
t)ula having its blades (ribs) furnished with a basal hjdrotheca, and in addition, on the outer side, 
numerous sarcothecse. Between the corbula and the stem the hydrocladium lias a varying number of 
hydrothecse. The gonotheca is pear-shaped. 

Material: 

"Ingoir St. 15 66°i8' N., 25°59' W., depth 330 fathoms -f- 0,75 

- - 35 65°i6' N., 55°o5' W., - 362 - 3,6' 

— - 81 6i°44' N., 27°oo' W., — 485 - 6,1 
"Thor" 63°i8' N., 2 1=30' W., depth 178 metres 

61-15' N., 9°35' W., - 872 - 
Iceland: 3 miles E. of Rjarnaroi, — 70 fathoms. 



^r^ 



_0 



Thecocarpus niyriophylliiiii is undoubtedly the most frequently occurring Aglaopheiiiid in the 
eastern part of the North Atlantic (fig. L). It is therefore highly peculiar that it should now have 
been met with for the first time by the "Ingolf in Davis Strait, where no specimen had previously 
been found. In Iceland waters also, reliable data have hitherto been extremely rare, though Sse- 
niundsson (1911 p. 105) records the species from the south-west point of Iceland, albeit under the 
name of Thecocarpus radicellatus. Wc can now add the further finds in these waters from Dannuuk 
Strait and east coast of Iceland. Thecocarpus iiiyriophylluin is a species belonging to the lower littoral 



HYDROIDA II 



93 



region of the warmer seas and tlie nj^per abyssal region; quite exceptionally it may penetrate deeper 
down, as seen from the above. In the boreal regions it is not altogether rare, and has even in a 
sing-le instance been met with in the cold area. 




._ looo m. 



Fig. L. The di,stribution of Thecocarpus myriophyllum in the northern Atlantic. 
In the hatched regions the literature notes a common, although scattered occurrence. 



Gen. Aglaophenia Lamouroux. 

Upright pinnate colonies with branched or nnbranched main stem, the apophyses bearing un- 
branched hydrocladia with several hydrothecte. All sarcothecte immobile. Gonothecge in a corbula 
formed by a metamorphosed hydrocladium; the corbnla blades (rib.s) are fnrnished with sarcothecse, 
but lack h\drothecas. 



Aglaophenia tubulifera Hincks. 

1861 Pliiniulanu tulmlifera, Hincks, A catalogue of the Zoophytes of vSonth Devon, p. 256, pi. 7, 

figs. I — 2. 
1868 Aglaophenia hibuUffra, Hincks, A history of the British Hydroid Zoophytes, p. 288, pi. 63, fig. 2. 

The colonies are pinnate with nnbranched or branched monosiphonic main stem divided into 
short internodia. The internodinm has close below the middle an apophyse directed obliquely forward 
and sideways, and three tubulose sarcothecse, a pair at the upper side of the apophyse and an unpaired 



Q. HYDROIDA II 



one in the median line near the base. The internodia of the hydrocladia have each a hydrotheca and 
three sarcothecse, a siipracalycine pair near the hydrotheca aperture and a median proximal of greatly 
varying length. The proximal sarcotheca is tubulose, and has an open connection with the lumen of 
the hydrotheca; in the outer parts of the hydrocladium, it forms a more acute angle with the branch 
axis than nearer the stem; its free parts are in forma typica up to ^Z, the length of the hydrotheca, 
in forma Billardi however, as a rule longer than the hydrotheca. The hydrotheca margin has an 
abcauline tooth, and on either side, between this and the hydrocladium, three, or more rarely four 
teeth. One or two internodial ribs are seen at the wall of the hydrotheca; at times an intrathecal 
rib may be indicated. 

The gonotheccc are situate on a hydrocladium which has broad lateral blades converging to 
a corbula; the basal pair of blades is as a rule free, and hangs out and downwards; there is a hydro- 
theca between the corbula and the stem. The gonothecse are pear-shaped. 

Material : 

"Thor", 35°57' N., 5°35' W., depth 740 metres. 

The synonymy of the species has been dealt with in detail on a previous occasion (Broch 
1912 p. 8) and notice has also been taken of the variations. Geographicalh', Aglaophenia tuhdifera 
is a southern species, only quite exceptionally passing beyond the limit of the boreal waters round 
the British Isles; it belongs more especially to the middle and lower parts of the littoral region. 



Family series Sertulariina nov. 
Family Sertulariidae. 

The hydrothecEe are bilateral in structure and furnished with closing apparatus formed of from 
one to four plates. The colonies form sympodia or monopodia with terminal growth point. The polyps 
have a more or less pronounced abcauline and basal blind sack with a low, non-digestive endodermal 
epithelium; they are therefore bilaterally symmetrical. 

Few families have been the subject of so much dispute as the Sertitlariidir^ both as regards 
limitation and also in respect of division into genera. The best foundation is that given by Levin- 
sen in his latest work (1913) where he comes to the same result as Stechow (1913). The latter 
writer here separates off the Syntheciidcr as a distinct family comprising those forms which lack the 
lid; but while Levi us en also discards this group and refers it to the family Lafoeidce^ Stechow 
considers the Syiifhcciidcr as an independent family, most nearly related to the Scrtulariidw sens, 
strict — a view in which we may fully concur, owing to the homogeneous organisation of the polyps. 
This principle for division is not very fully dealt with by Lev in sen, and in particular the special 
organisation of the abcauline blind sack and its endodermal peculiarities seem altogether to have 
escaped his attention. This is suggested, as already mentioned, by his reference to a blind sack in 
Lictorella pinna/a (G. (). Sars) which from a purely anatomical point of view is hardly tenable. Com- 



HYDROIDA 11 Qc 



mon to Syiitlicciidir and Scrtulariidcr is also the exterior ectoderm lamella, which forms an inner wall 
covering to the hydrothecce; a parallel formation is, it would seem, found only in Aglaoplicniidw^ 
where it is less pronounced. P'rom the anatomical agreement of the polyps in the two families, and 
the fundamental differences in the structure of the polyps as compared with the remaining thecaphores, 
I have found it most correct to take the two families together in a distinct family series Scrtiilariina. 

With regard to division into genera, however, I can on the whole agree with Levinsen, as 
will be seen from the following. Nevertheless it should be noted that the generic subdivision is still 
far from satisfactory. A considerable amount of anatomical investigation will be required before we 
can obtain a thoroughly adequate foundation here, and the present material, unfortunately, is not suit- 
able for such studies. 

In face of the above diagnosis, it may l:)e objected that a genus such a.i Diphasia lacks the 
blind sack, at any rate, appears to do so. This point is not without importance, and has its own parti- 
cular interest in consideration of the gentis from a iihylogenetic point of view. On closer examination 
of the group of species which Levinsen classes together in the genus Scrtiilayclla, we find that 
there are here, as a matter of fact, two distinct anatomical groups, which ought really to be separated 
as independent genera. The more restricted genus Sertiilarclla will then comprise the species in which 
a closing apparatus consisting of 3 or 4 flaps is found together with polyps having fully de\-eloped 
abcauline blind sack; this class includes the great majority of .species. On the other hand we liave 
a group of .species with the same sort of closing apparatus, but with polyps in which tlie blind 
sack is rudimentary or entirel\' lacking as far as can be seen from external observation. For this 
group, then, a special genus should be established. The group in question exhibits a close affinity 
to Thyroscyplms, which again forms a link with Caiiipaiinlhiida", and from this genus we must pre- 
sume that the entire family has its origin. A species such as Sertiilarrlla faiiian'sca (Linne) belongs 
to this group of the SrrtithirrUti, and represents the transition stage to genera with rudimentary blind 
sack, Diphasia and Dyiiameuia. From the second group, again, are derived the remaining genera with 
their marked lines of development in the closing apparatus. Taking into consideration both the organ- 
isation of the hydranth, and the structure and development of the closing apparatu.s, we come to fixed 
lines of development within the family, which are best illustrated by the following scheme: 

Odonfofbcca Hydrallii/ai/ia Thnjaria 

X ! /' 

Scrtularia 
Diphasia Dynaniena- Abictiiiaria 

a. Polyps wUh rudimentary blind sack. — Soiularclla — b. Polyps with l)liiid sack. 

Tliyroscyphus 



96 



HYDROIDA II 



Gen. Sertularella Gray. 

Upright colonies with sympodial growth. The opening of the- ludrotheca is furnished with 
three or four marginal teeth, between which are attached as many triangular opercular plates closing in a 
pyramid over the aperture. 

The definition here agrees with that given by Levinsen (1913 p. 30). The genus seems, how- 
ever, to form a somewhat heterogeneous collection of species which should, probably, from the struct- 
ure of the polyp, be divided into two groups or genera. Of these groups, Sertularella sens str. will 
.then comprise species with abcauline blind sack, while in the other group, we have species where 
this is rudimentary or indiscernible on external observation. -The latter group leads, as above menti- 
oned, to Diphasia aiid Dynamena, while the former gives the point of origin for the remaining genera 
of Sertulariidce. The most primitive group is that of the species without visible blind sack. 

Sertularella tamarisca (Linne) Levinsen. 
1758 Sertularia taviarisca, Linne, Systema naturae, ed. 10, p. 808. 
1893 Sertularella tamarisca, Levinsen. Meduser, Ctenophorer og H)droider, p. 58. 

Upright, somewhat irregularly branched, as a rule pinnate colonies, without distinct main stem. 
The hydrotheca;, which have a tripartite lid and tridentate opening margin, are set in two rows along 
the branches, a pair of liydrothecte oppositely placed on each interuodium. The hydrothecse are very 
large, almost cylindrical, with the distal half free and highly diverging from the branch. 

The male gonothecje are reversed conical, compressed distalh- with a small tooth on either side 
and a short cyHndrical neck centralh- placed. The females are of the same shape, but have three 
distal broad blades, each furnished with a longitudinal indented median ridge; the three blades close 
in to a pyramid and form a large external marsupium, in which the larvte are developed. 

Material : 

"Ingolf" St. II, 64°34' N., 3i°i2' W., depth 1300 fathoms, 1,6° 

— - 87. 65°o2,3' N., 23^-'56,2' W., — 110 — 

— - 95. 65"i4' N., 30°39' W., — 752 - 2,1° 
- 98, 65=38' N., 26°27' W., - 138 - 5,9° 

— - 144, 62°49' N., 7°i2' W., — 276 — 1,6° 
"Thor" 63=30' N., 20°i4' W., - 80 metres 
Iceland: 6 miles W. of Isafjord, depth 55 fathoms 

5 — E. of Seydisfjord, — 135 — 
63°2i' N., i7°i5' W., _ 58 - 

The Faroe Islands: 16 miles S. by E. of south point of Nolso, depth 80 fathoms. 

Sertularella taiiiarisea presents, as a matter of fact, a somewhat alit-u impression among the 
remaining Sertularella species, and has led an unsettled existence, now in this genus, now in Diphasia 
or Dynamcna. The paired arrangement of the ludrotheCLe and the remarkable female gonotheCcC of 



HYDROIDA II 



97 



the species, with the marsupial chamber resembling that of Diphosia fullax (Johnston) and Diphasia 
rosacea (Linne) have led to its being freqnenth- referred to this genus. The state of the material 
did not permit of a quite certain investigation of the polyps, but as far as it was possible to judge 
it has a quite rudimentary blind sack, which brings the species nearer to Diphasia. On the other 
hand, the closing apparatus is altogether of the same type as Sertularella., thus removing tlie species 
again from Dipliasia. The most natural thing would doubtless be to consider Serlularella tamarisca 
as the type of a distinct genus, which in a certain degree forms a link between the true Scrlnlaria 
species and Diphasia. This would demand, however, in the first place a closer study of the structural 




2 00 rrt. .___.^oom ,_ i quo m. ,_ , .^.. 2 ooo m. 

Fig. LI. The distribution of Serlularella tamarisca in the Nortliern Atlantic. 
In the hatched regions the literature notes a scattered occurrence without giving particular data. 

conditions of the species, and as my material is not suited to the purposes of such investigation, I 
have for the present refrained from establishing the new genus here. 

It is not altogether easy to determine witli certainty the biogeographical character of the 
species. Sertnlarclla taviarisca is not a form of frequent occurrence, and is never met with in large 
numbers at a time; on the contrary, it is as a rule taken in single specimens, so that the species 
appears to be somewhat of a raritw Further study seems to show that it is a boreal species capable 
of penetrating slightly into the arctic area and even more into warmer waters. Towards the north, 
it comes up into the White Sea, and towards the south, as we know, it penetrates into the Mediter- 
ranean. In the waters investigated (fig. LI) the species has not infrequently been found in the eastern 
part of the boreal region, while it has only once been met with in Davis Strait; it never j^enetrates 
into the cold area, despite the fact that its wide bathymetrical range would seem to suggest a con- 

Tlie Ingolf-Expedilioii. V. 7. 



J3 



98 



HVDROIDA II 



siderable elasticity in respect of physical conditions. The chief occurrence of tlie species falls in the 
lower part of the littoral region and the upper part of the abyssal. 

Sertularella tricuspidata (Alder) Hi neks. 
1856 Srrtulariii frtnispidafa^ Alder, A notice of some new genera and species, p. 356, pi. 13, figs. 1 — 2. 
1868 Srrtxlarrlla Iriciispidata, Hincks, A History of the British H\droid Zoophytes, p. 239, pi. 47, fig. i. 

Upright colonies with pinnate or quite irregularh' bushy ramification; in the pinnate colonies, 
the branches are alternating or snbaltcrnating, not infrequenth- the)- may themselves be dichotomi- 
cally or pinnately branched ; the branches are often bent or twisted. The nionosiphonic stem and 
branches are segmented; each internodium has a hydrotheca. The liydrothecte are situate on the 
distal part of the internodium, and are cylindrical or slightly barrel-shaped, with their narrowest part 
immediately below the aperture; they have three teeth of equal size on the aperture margin, the one 
median adcauline; in the sinuses between the teeth, the three triangular plates of the closing apparatus 
are attached. The adcauline wall of the hvdrotheca has a free distal part between lialf and two-thirds 
the length of the hydrotheca. The polyp has a well-developed abcauline blind sack. 

The gonothecse are attached under the base of the hydrothecse. The\- are oval to pear-shaped, 
with a short and narrow, reversedly conical, distally central neck, and with deep transverse furrows. 

Material: 

"Ingolf", beach of Jan Maven. 

- '"^t- 3 63°35' N., io°24' W., depth 272 fathoms 0,5° 

- - 34 65^17' N., 54°i7' W., - 55 _ _ 

- - 54 63°o8' N., i5°4o' W., - 691 - 3,9° 

- - 87 65°o2,3' N., 23=56,2 W., - no - _ 

- - 95 65°i4' N., 3o°39' W., - 752 - 2,1° 
"Thor" 65°52' N., 23=58' W., — 62 metres 

65°29,5' N., 24°63' W., - 40 - 

— 64°o2' N., 22°33' W., _ 34 _ 

— 63°3o' N., 20° 14' W., -- 80 — 
(irec-nland: nioutli of Nerak (depth not stated) 

Hunde-Eiland ( — - — ) 

Egedesminde, deptli 30—40 fathoms 

Store Hellefiskebanke, — 24 — 

Sukkertoppen, on Boltriiia (without further details) 

Frcdcrikshaab ( — — _ ) 

Iceland: P.akkefjord, depth 25—32 fathoms 

Lonafjord, — 40 

Malarif (deptli not stated) 

Resdarfjord, — 60—80 — [labelled Serin la rrlhi polyzofiias\ 

63°2i' N., 1 7° 1 5' W. — 58 — 



HYDROIUA II 



99 



Iceland: Vestmano, depth 25 fathoms 

10 miles W. of Akranes (depth not stated) | labelled Srrtii/iirc/la polyzomas\ 
Bredebuyt, depth 7 — 12 fathoms 

65^00' N., 24°38' W., — 22 
Onundarfjord — 10 — 

Adalvik (depth not stated). 
The Faroe Islands: 7 miles N. b}- K. of AI_\ggemes point, depth 57 fathoms 
6 — N. by W. of Store Kalso, ~ 60 

Deep hole at north point of Nolso, — 100 — 

5 miles S.S.E. of Iiispen, — 50 — 

Scrfularclln triciispidata is a circumpolar arctic species which is extremely nnmerons in arctic 
waters. From there is penetrates far down into the boreal area (fig. LII) where it is one of the most 
common species, especially ronnd the Faroe Islands, Iceland, and off West Greenland. Along the east 
coast of Greenland, however, it is distinctly rare. Its infreqnent occurrence off the north coast 
of Iceland on the other hand, should probably rather be apparent, as the result of insufficient in- 
vestigations. Along the west coast of Norway, Scrtnlan-lla tricnspidata goes southward as far as 
Bergen; according to the literature, it is also met with near the British Isle.s, but we have no certain 
data from here, so it would seem that this must be about the limit of its distribution. Bathymetri- 
callv, it belongs to the littoral region, exceptionally, however, it may, as shown by the find at the "In- 
golf" St. 95, penetrate quite far down into the abyssal. 




.^■v«^ '^i 



200 m. doom. t p ^o m. .._.. 

I'ig. LII. The distribution of Sertularella triciispidata in the Northern Atlantic, 
In the hatched re>(ions the Uterature notes a scattered occurrence. 



_. 2 000 m. 



13 



lOO 



HYDROIDA II 



Sertularella amphorifera Allman. 

1877 Sertularella amplwrifera, Allman, Hydroida of the Gulf Stream, p. 22, pi. 15, figs. 8—10. 

1912 Serhdarella amphorina, Bedot, Materiaux pour servir a rhi.stoire des Hydroides, 4™' periode, p. 352. 

Upright slender colonies with monosiphouic hydrocaulus. Stem and main branches slightly 
prominent. The basal part of the stem is straight, irregularly segmented, without hydrothecse and 
branches; higher up, it becomes regularly segmented, like the branches, with a hydrotheca on the 
distal part of each internodium. The branches arise in irregular alternation, and may themselves 
again ramify; like the hydrotheca-bearing part of the main stem, they are bent zigzag fashion. The 
hydrothecse are large, cyhndrical, slightly curved, 
with three equal sized, markedly prominent 
teeth,* and in the sinuses between them three 
large triangular lid plates. The hydrotheca is 
attached to the branch by a narrow base. The 
polyp has a distinctly prominent abcauline 
blind sack. 

The gonothecge proceed from below the 
base of the hydrothecse. They are a slender oval 
to pear-shaped, with a distally central narrow 
neck, and distinct transverse furrows; the neck 
passes evenly over into the gonotheca. 




11. Sertularella amphorifera 
from "Ingolf" St. 54. 
Part of a branch (X 20). 
leca of the stem with the basis 
of a branch (X 40). 



Material : 

"Ingolf St. 7, 63°i3' N-, i5°4i' W.; depth 600 fathoms, 4,5° 
- - 54, 63°o8' N., 15=40' W.; - 691 - 3,9° 

Nutting (1904 p. 88) who had only some fragments of Allmau's type specimen to work on, 
states that Sertularella amphorifera has possibly four hydrothecal teeth, and he gives some drawings 
where four such teeth are markedly in evidence, as if his specimen had been intact, and not, as he 
himself expressly notes in the text, defective. Billard (1906 p. 183) on the other hand, reports the 
species as distinctly tridentate, and this is also plainly to be seen from my specimens (fig. LIII). Be- 
tween two branches on the stem, the ninnber of hydrothecre varies from two to five. 

Sertularella amphorifera is evidently very closely related to Sertularella triciispidata, extreme 
variants of whicli may i)reseut a strong resemblance to the former. On the whole however, Sertula- 
rella amphorifera seems to be of considerably more open growth, wliile its finer structure and long, 
slender internodia, together with the strongly projecting hydrothecse, give it a txpically different 
appearance from Sertularella tricuspidata^ as is apparent at the first glance. 

The finding of Sertularella amphorifera so far to the north is highly interesting. It was pre- 
viousl)- known only from the sea off Florida at Double Headed Shot Ke>-, 471 fathoms, and from the 
west coast of Africa, where it was taken at 882 metres' depth. The species thus belongs to the warmer 
parts of the Atlantic aby.ssal region, and moves up, in the warm, deep water layers, to the deep off 
the south-east coast of Iceland. 



HYDROIDA II joi 



Sertularella polyzonias (Uune) Gray. 
1758 Sertidaria polyzonias^ Linne, Systema naturae, ed. 10, p. 813. 
1848 Sertularella polyzonias van «, Gray, List of the specimens of l)ritisli animals, p. 68. 

Upright colonies with irregularly branched monosiphonic hydrocaulus, no distinct main stem. 
The branches are divided by oblique nodes into internodia, each bearing a hydrotheca, turning alter- 
nately to either side. The hydrothecse are smooth or slightl>' wrinkled tran.sversely, barrel-shaped, with 
a somewhat expanded opening part; the opening margin has four low and broad teeth, between which 
are attached the four triangular lid plates. The adcauline wall has a longer or shorter free part, 
according as the hydrotheca diverges more or less sharph' from the branch. The pohp has a well- 
developed abcauline blind sack. 

The gonothecae proceed from close under the base of the hydrothecae. They are egg-shaped, 
deeply furrowed transversely throughout their entire length, and have four markedh' prominent strong 
teeth about the distally central opening. 

Forma typica: fine and low colonies. 

Forma gigantea (Mereschkowsky): large robust colonies. 

Material: 

Forma typica: 

Iceland: Bredebugt, depth 35 fathoms (transitional to forma giganira). 

63=20' N., 20°i4' W., depth 80 metres. 
The Faroe Islands: 6 miles N. by W. of Store Kalso, depth 60 fathoms. 

Forma gigantea: 

"Ingolf" St. 127 66°33' N., 2o"o5' W., depth 44 fathoms 

Greenland: Akudlek — 30-60 — [labelled Sertularella polyzonias] 

Jakob.shavn (depth not stated) [ — — — ] , 

Egedesminde — - — 

Store Hellefiskebanke (without further details) 
— — depth 32 fathoms 

Godthaab (witliout further details) |labelled Sertnlarella polyzonms] 

Davis Strait, 67=34' N., 55"29' W. | — — — I 

Sukkertoppen on Boltenia (depth not stated) 
Kara Sea, "Dijmphna" [labelled Sertularella polyzonias], 

Sertularella polyzonias is divided by many writers into two species, the gigantic arctic form 
being regarded as a distinct species, Sertularella gigantea Mereschkow.sky. Kirchenpauer (1884 p. 
34) has already drawn attention to the existence of intermediate forms between the two, which cannot 
show a single qualitative difference, the latter for instance, being distinguished merel>- by the fact 
that all dimensions are harmoniously increased. The very fact that this form belongs to the arctic and 
antarctic water layers, while the other is quite cosmopolitan, warns us to be careful about regarding them 
as distinct species. Geographical .studies on the variations of hydroids have shown (cf. Broch 1909, 



I02 



HYDROIIJA II 



1913, 1914) that the dimensions may here quite commonly become coarser within the same species as 
the temperature decreases. In SerhilarcUa pnlyzonias forma gigantea, this common law has been fol- 
lowed to an extreme, while the transition forms are comparatively few. That they exist, however, 
is plainly evident from the present material, where in particular certain colonies from Jakobshavn, 
Greenland, and all those from Bredebugt take up a doubtful intermediate position. 

Voxm2igigantca (fig. LIV) is a typical arctic (and antarctic) character form, only exceptionally capable 
of penetrating into the boreal region. It is extremeh' common in West Greenland waters, and is also 
known from East Greenland; occasionally also from the north coast of Iceland. Forma /^//W?, on the other 




200 m. 600m fooom. . 1000m 

Fig. LIV. I'"!nds of Seititlarella polyzoiiias forma typica • and forma gi);antca 4- iu the Northern Atlantic. 
In the hatched regions the literature notes a common occurrence of the forma typica. 

hand, is cosmopolitan, and occurs also, albeit less frequently, in arctic waters. In the boreal area, it 
is particularly numerous iu the eastern parts. Both forms belong to the middle parts of the littoral 
region, and rarely move down into the deep sea region. 



Sertularella Gayi (Lamonroux) Hiuck.s. 
1821 Scrtularia Gayi, Lamouroux, Expo.sitiou methodique des genre.,, p. 12, pi. 66, figs. 8—9. 
1868 Sertularella Gayi, Hincks, A History of the British Hydroid Zoophytes, p. 237, pi. 46, fig. 2. 

Upright, irregular doubly pinnate colonies with distinctly prominent pohsiphonic main stem 
and main branches. The outer branches are almost regularly pinnately branched often with their minor 
branches secondarily ramified. The outer branches are divided by indistinct oblique joints into short 
internodia, having on their distal half a large hydrotheca; the hydrothecce are directed alternately to 



HVDROIDA II 



103 



either side in tlie broad j)laue of the coloiu. The h\drotlieca lias a free adcauhiie distal wall i)art, 
half as long as the hydrotheca or somewhat less, about i'/,, times the opening diameter. The hydro- 
theca has its greatest breadth at the middle, and narrows down both towards the base and towards 
the opening, which is set perpendicular to the axis of the hydrotheca. The free portion of the adcau- 
line wall is as a rule furnished with somewhat faintly marked transverse furrows. The opening margin 
has four low teeth and four triangular lid plates in the sinuses between them. 

The gonothecas proceed from the branches close under tlie base of the hydrothecic. They are 
oval, more or less furrowed transversely in the distal half, and have distally a narrow central opening 
witl) two diametrically opposite short broad teeth. 




100 m. 



. s 000 m. 



600 m. .^ 1000 m. 

Fig. LV. The distribution of Seitnliiiel/a Gayi m the Northern Atlantic. 
In the hatched region.s a common although scattered occurrence is stated in the hterature without precise data. 



Material: 

"Ingolf" St. I 62°3o' N., 8°2i' W., 

- - 55 63=33' N., 15=02' W., 

— - 85 63°2i' N., 25=21' W., 

- - 94 64=56' N., 36=19' W., 

— - 98 65=38' N., 26^27' W., 
"Thor" 64=06' N., 23=14' W., 
Iceland: Ingolfshofdi 9'/, miles in N. by E.' ,P:., depth 53 fathom 
The Faroe Islands: 60=23' N., 8' 55' W., - 225 — 



depth 132 fathoms 7,2 

— 316 - 5,9 

— 170 - — 

— 204 ^ 4,1 = 

— 138 - >9° 

— 98 metres | labelled Srrtiihrclla polyzoHias\ 



J.Q. HYDROIDA II 



Sertularella Gayi is an atlantic warm-water species, which in the northern waters (fig. LV) exhibits 
an easterly distribution. It belongs to the deeper littoral and upper abyssal regions, where it is parti- 
cularly frequent. In the south-eastern part of the boreal area it is quite common, and moves hence 
down into the cold area in the Faroe Channel; it is not altogether rare off the south coast of Iceland, 
where it seems now and again to have been confused with Sertularella polyzonias. The "Ingolf" has 
a single specimen from St. 94, so that the species can also occur in deep water off the south-east 
coast of Greenland, outside the mouth of Danmark Strait, where the deeper parts are still covered 
with warmer atlantic water layer.s. 

Sertularella tenella (Alder) Hinck.s. 
1856 Sertiilaria tei/ella, Alder, A notice of some new genera and species, p. 357, pi. 13, figs. 3—6. 
1868 Sertularella tenella, Hincks, A History of the British Hydroid Zoophytes, p. 242, pi. 47, fig. 3. 

Upright, unbranched or slighth- branched openly constructed colonies with monosiphonic h>dro- 
caulus. Stem and branches are divided by joints into not very long internodia, each having on 
its distal part a very slightly imbedded h>drotheca; pro.ximally, the internodium is furnished with a 
pair of rings. The stem and branches are bent to an angle at the nodes, which gives them a mark- 
edly zigzag course. The hydrotliecas are large, about as long as the internodia, elongated oval, 
with somewhat more cylindrical opening part; they are distinctly furrowed transversely between the 
base and the cylindrical opening part. The aperture is set perpendicular to the longitudinal a.xis of 
the hydrotheca. The opening margin has four low teeth, and in the sinuses between them four tri- 
angular lid plates. The polyp has a well-developed abcauline blind sack. 

The gonothecse proceed from stem and branches close under the base of the hydrothecse. They 
are oval to more pear-shaped, transversely furrowed throughout their entire len_gth, and furnished with 
a distal central short, almost cylindrical neck. 

Material: 

"Ingolf" St. 94 64°56' N., 36°i9' W., depth 204 fathoms 4,1° 
- - 95 65°i4' N., 30°39' W., - 752 - 2,1° 

.\s a synunym to this species I have previously (1909 p. 126) noted Sertularella pellueida. Ja- 
dcrholni lias, however, (1909 p. 99, Taf. XI, figs. 8— n) given a closer study of this species, from 
wliich it appears that it does not belong here, its entire structure being different, and the colonies 
more resembling those of Sertularella fusiforiiiis. 

Kranip (1914 p. 1037) characterises Sertularella tenella as a cosmopolitan species. This must, 
however, as will be seen from the chart (fig. LVI) be taken with .some little reserve. The species is alto- 
gether more sporadic in its occurrence witliin the northern waters, save probably for the tracts immediately 
round iIk- P>ritis]i Isles, where it appears to be more common. Otherwise, it follows in the northern areas the 
same laws as do the warmer atlantic species, and is somewhat rare in the strictly boreal water layers. 
V. Lorenz, (1886) mentions the species from Jan Mayen, l)ut this determination would seem, from the 
remaining data, to be somewhat uncertain. 



HYDROIDA II 



105 




00 m. __«««_. 600 m. •-■. * . ^ 1000 m. 2 000 rn. 

Fig. LVI. Finds of S,i-tit/aiv//a ti-iwtlu in the Northern Atlantic; 
In the hatched regions the data are not altogetlier precise, (o doubtful locality). 



Sertularella fusiformis Hi neks. 
1861 Scrtulana fiisifor>iiis^ Hincks, A Catalogue of the Zoopli\tes of South Devon, p. 253, pi. 6, figs. 7 — 8. 
1868 Sertularella fiisiforiiiis, Hiuck,s, A Hi.story of the British Hyclroid Zooplntes, p. 243, pi. 47, fig. 4. 
1907 Sertularella pellueida^ Jaderholm, Uber einige nordische Hydroideu. 
1909 Sertularella pellucida, Jaderholm, Northern and Arctic Invertebrates, p. 99, Taf. 11, figs. 8 — 11. 

Open and finely btiilt, zigzag and sHghth' branched upright colonies with Uionosiphonic stem. 
The stem and branches are divided into short internodia which form an angle one with another, and 
are more or less distinctly ringed, more rareh- quite smooth. From the same iuternodiiun may often 
proceed two or three branches, or simple internodia. The large, somewhat spindle-shaped hydrothecae 
are situate on the outer half of the internodium, and are very slighth- embedded; the opening part 
is again as a rule somewhat expanded; the aperture is set perpendicularly to the axis, and has four 
not very prominent teeth, between which are attached four triangular lid plates. 

The gonothecae are attached to the branches or stolons. They are elongated o\-aI to egg- 
shaped, in the latter case with the broader part somewhat below the middle. The gonotheca has a 
distal central aperture with four strong teeth. 

Material : 

"Ingolf St. 3 63°35' N., io°24' W., depth 272 fathoms, 0,5". 

The Ingolf-Expedition. V. 7. 14 



io6 



HYDROIDA II 



Sertularella fusiforniis assumes a highh- characteristic appearance from the peculiarity that it 
has often on stem or branches two or three short branchlets proceeding simnltaneoiisly from the same 
point, these short branchlets consisting of a single internodium, or more rarely a couple, with large 
hydrothecjE almost terminally placed. An excellent picture of this is given by J ad er holm (1909 Taf. 
II, fig. 9). His specimens undoubtedly belong to Scrhilarella fnsiformis, and are only remarkable in 
having the internodia entirely smooth; here, however, all transition stages occur, so that we are not 
warranted in setting aside the specimens on such ground as types of a distinct species. 

SerfnlarcUa fusifornns is probably a warm atlantic species, but its occurrence is little known. 
In the waters investigated, it is previously known from the Hebrides, and from the Clyde Sea area; 
to these, Jiiderholm adds a single find from Spitzbergeu, and the species has now also been taken 
bv the "Ingolf" about midway between tlie Faroe Islands an3 Iceland. 



Sertularella rugosa (Linn e) Hi neks. 
1758 Scrtiilaria rugosa, Linne, Systema naturae, Ed. 10, p. 809. 
1868 Sertularella rugosa, Hincks, A History of the British Hydroid Zoophytes, p. 241, pi. 47, fig. 2. 

Upright, irregularly branched small colonies without pronounced main stem; the latter is mono- 
siphonic. The colony is divided b\' oblique nodes into short internodia, each bearing a Indrotheca 
directed alternately to either side, and situate on the upper half of the internodium. The hydrothecse 
are broad oval or barrel-shaj^ed, with deep trans\'erse furrows, which are particularly marked on the 
abcauline side, where a very deep furrow is alwa\s foinid immediately beneath the aperture. The 
opening forms an angle with the hydrotheca axis, and is turned awa\- from the branch; it is furnished 
with four low, often somewhat indistinct teeth, between wliich four triangular lid plates are attached. 
The polyp has a large abcauline blind sack. 

The gonothecie proceed from the internodia close under the hydrothecae. 
They are egg-shaped or more oval, with deep transverse furrows, and have distally 
a central broad opening, surrounded by four short strong teeth. 

JNIaterial : 

Jan ]^Iayeu, depth 15 fathoms (East Greenland expedition). 
Iceland: (iriudavik (depth not stated) 

10 miles W. of Akranes, on alga; 
Sl\kkisholui, depth 30 fathoms 
Bredebngt (without further detail.s) 
The Faroe Islands: vSolmunde, on alga; 

Thorshavn, on algte, depth 3 — 4 fathoms. 
Vestmanha\-n, — 3o — 4 — 

The available illustrations of Srrtnldrrlla rugosa are very little characteristic, and this applies 
especially to Nutting's (1904 pi. 17, fig.s. i — 5) which present an entirely misleading impression, in- 
asmuch as they suggest that the hydrothecse are distinctly ringed. A new drawing is therefore given 
here (fig. LVII) showing the deep transverse furrows; particularly characteristic is the deep abcauline 
furrow beneath the aperture. 




Fig. LVII. Hydrotheca. 

of SerHilarclla rugosa 

from Ilerlo near Bergen 

(X 40). 



HYDROIDA II 



107 



Sertularella riigosa must be characterised as a boreal species, ha\-ing its bathynietrical distri- 
bution in the upper half of the littoral region, though it does not often penetrate up into the tidal 
zone. Kirch enpauer (1884) records it as found at Greenland, but there are no subsequent finds 
recorded from there. In the areas investigated (fig. LVIII) it has, it will be seen, an easterly distri- 
bution from Iceland to up in the Barents vSea, but its occurrence in the purely arctic area is quite 
sporadic, while on the west coast of Norwa}', for instance, it is a characteristic species in the laminaria 
zone. New finds are those from the Faroe Islands, wiiere the species might be expected to be found 
from its occurrence off the coasts of Iceland, the British Isles, and Norway. 




200 m. 600 m. .■..« .looom. 2 000 m. 

Fig. LVIII. Distribution of St itii/oi;l/a rugosu in the Northern .Atlantic. 
In the hatched regions a common occurrence is noted. 



Diphasia Agassiz. 

Upright colonies, the hydrothecce having a horizontal or slightly obliquely situated aperture 
without distinct teeth, but as a rule with an adcauline sinus, in which the large single opercular plate is 
attached. The polyps lia\-e, as far as can be seen from external observation, no abcauline blind sack. 

This definition differs in one important feature from that given by Levinsen (1913 p. 309I, 
the organisation of the polyps lieing taken into con.sideration. We thus obtain a stronger and more 
natural limitation, and the genus then practically coincides with the group Endipliasia Broch. It has 
long been a doubtful question whether the two 'gxo\\^<, Eitdiphasia ^\\A Abietinaria ^\\ov\A be assigned 
generic rank or not. attention having previou.sly been paid only to the form of the hydrotheca as the 
decisive point, and distinction thus made between species having more cylindrical hydrothecje or hy- 

14* 



j08 HYDROIDA II 



drothecffi expanding distally (Eudiphasia) from those in which the hydrothecae are bottle-shaped (Abie- 
tinaria). There are, however, transition forms, and the great variation in the hydrothecse in most spe- 
cies renders a hmit such as that so drawn extremely vague. 

We now find, however, that the structure of the polyp is different in the two groups, the blind 
sack being only in the latter found in full development. This is an organisational feature of so con- 
siderable importance as not only to warrant, but even to demand, a generic distinction between the 
two groups, which also on the whole present interesting points of difference in the gonangia. In 
Diphasia, we find that the female gonothecse are as a rule furnished with spinous or leaf-shaped out- 
growths, wliich very often fold in together, forming a distal chamber for the brood, a marsupium. 
This is a biological phenomenon, and from a phylogenetic point of view of less importance; on the 
other hand, it is interesting to note that it here appears to occur as a constant characteristic in a 
whole series of related species. It is also worth noting that this feature is likewise found in Scrtida- 
rella tamarisca (Linnel a species which appears to form a link between Scrhdarella and Dipliasia. 

Diphasia fallax (Johnston) Al. Agassiz. 
1847 Sertidaria falla.x^ Johnston, A Histor)^ of the British Zoophytes, p. 73, pi. 11, figs. 2, 5, 6. 
1865 Diphasia fallax, Al. Agassiz, Illustrated Catalogue, p. 142. 

Upright pinnate colonies with more or less pronounced monosiphonic main stem, and as a rule 
with convex foreside. Stem and branches are divided into internodia, each bearing a pair of oppos- 
itely placed hydrothecse. The branches proceed alternately from the stem, and are themselves often 
sparsely branched, frequently with tendril-like terminal parts. Between two successive branches on 
the same side of the stem there are two to four hydrothecse, the one of them being at the corner of 
the branch. The hydrothecse are deeply embedded, with a free distal part of the adcauline wall, in 
length equal to the opening diameter, or slightly less. The aperture is round, the margin with ad- 
cauline sinus, in which the large opercular plate is attached. The greatest diameter of the hydrotheca 
is at the opening. 

The gonothecse are situate on tlie upper side of the branch or on the fore side of the colony. 
The males are pear-.shaped, witli four distal short broad spines, and a short conical to cylindrical cen- 
tral neck. In the females, the four spines have developed into four broad triangular blades, which 
close in together over a distal brood-cliamber in whicli the larval development takes place. 
Material : 

"Ingolf vSt. 3, 63°35' N., 10=24' W., depth 272 fathoms 0,5°. Variety. 

— - 51, 6414' N., I4°22' 

- - 87, 65°o2,3' N., 23°56,2' W., 

- - 93, 64°24' N., 35° 14' W., 

- - 94, 64=56' N., 36=19' 

— - 95, 65=14' N., 30=39' 

— - 96, 65°24' N., 29=00' 

— - 98, 65°38' N., 26=27' 

- - 115, 70'50' N.. 8=29' 



w., 


— 


68 


- 7,32' 


w., 


— 


no - 


— 


w., 


— 


767 - 


1,46' 


w.. 


— 


204 - 


4,1° 


w.. 


— 


752 


2,1° 


w., 


— 


735 


1,2° 


w.. 


— 


138 - 


- 5,9^ 


w., 


— 


86 


0,1° 



HYDROIDA II jQQ 



"Thor" 66°i9' N., 23°27' W., depth 115— 120 metres. Variety. 
- 65^52' N., 23°58' W., _ 62 - 

63=30' N., 20° 1 4' W., _ 80 — 

Greenland: Davis Strait, — 100 fathoms (without further details) 

Iceland: 5 miles E. of Seydisfjord, — 185 — 

Ingolfshofdi g'/, miles in N. by E.'/^E. (depth not stated) 
Vestmano, depth 50 fathoms 
Skagi, — 40 metres 

6 miles W. of Iceland (without further details) [labelled Diphasia rosacai] 
0nundarfjord, depth 10 fathoms [ — — — | 

65°39' N., 28°25' W., depth 553 fathoms. 
Between Iceland and The Faroe Islands: depth 270 fathoms (without further details). 
The Faroe Islands: 8 — 10 miles N. of The Faroe Islands ( — — — ) 

7 miles N. by E. of Myggenses point, depth 57 fathoms 
6 — N. by W. of Store Kalso, — 60 — 

• Deep hole at north point of Nolso, — 100 — 

Boronses 13 miles in N. 75°W. — 30 — 

16 miles E. by S. of south point of Nolso — 80 — 

It may be a question whether Diphasia fallax cannot exceptionally be confused with Diphasia 
Wandeli Levinsen, if the latter species, as SEemundsson opines, can occur with only two rows of 
hydrothecse on the branches. There are also in the present material colonies of Diphasia fallax dif- 
fering in appearance, so that there is some ground for further considering the point. 

Saemundsson (igii p. 97) mentions having found colonies of Diphasia Wandeli W\\X\ only two 
rows of hydrothecae on the branches, and with female gonothecce, which, however, from his drawings, 
agree entirely with Diphasia fallax. According to a footnote in Stem un dsson's work (1911 p. 98) 
Levinsen should, after seeing the colonies, have expressed as his opinion that they must rather be 
regarded as aberrant colonies of Diphasia fallax than as representatives of Diphasia Watideli. Now 
Ssemnndsson points out, in the same place, that a colony of Diphasia Wandeli from the Norwegian 
Sea, which he has had occasion to study, had on the basal parts of eight of its branches only two 
rows of hydrothecse, while the outer parts of these branches, and all the remaining ones throughout 
their length, had three rows of hydrothecje. This reminds one not a little of the aberrant Thiifaria, 
which is further described in "Fauna artica" (Broch 1909 p. 177). As the colon}- described by Ss- 
mnndsson is sterile, it cannot be determined with certainty. It is probably a Diphasia iVandeli, but 
it might also be imagined that it could be a mutant of Diphasia fallax^ thougli this is less likely to 
be the case. Typical female colonies of Diphasia Wandeli with gonothecse have not yet been found; 
as to the males, we know that the\- differ from Diphasia fallax in having eight instead of four distal 
spines on the gonothecje, these eight spines being arranged in pairs. It is therefore impossible to say 
with certainty which species Ssemnndsson had before him, as long as typical and fertile female 
colonies of Diphasia Wandeli have not yet been found. Stemundsson's colonies form, moreover, 
only the extreme link in a continuous variation series, of which the central one is Diphasia fallax. 



no 



HYDROIDA II 



The "Ingolf brought back from several of its stations colonies of the same type described by 
Ssemnndsson as Diphasia IVandeli. They are stiffly built, with a distinctly marked, often some- 
what darker and plainly segmented main stem. Each internodium has a pair of liydrothecae and a 
branch, directed alternately to either side, so that in these colonies, we have constantl\- two hydrothecct 
between two successive branches on the same side of the stem; of these two h^^drothecse, the one (the 
lower) is situate in the corner b\- the branch. In the most extreme specimens of this variant group, 
we find single undivided branche.s. This variety- is represented b\- a particularh- pure type in specim- 
ens from the "Ingolf" St. 3 and St. 93. In these colonies, tliere is no pronounced fore or rear side as 
generally seen in Diphasia fallax. This must doubtless be taken in connection with the fact that the 




._ tO':iQ rn. 



Fij<. LIX. The distribution of Diphasia fallax in the Northern Atlantic. 
In the hatched regions a common occurrence in reported (+ the variety spoken of in the text). 

most marked representatives of the variety are attached to a firm underlayer, stones or mollusc shells, 
and not, as is mostly the case with this species, to stems of other h>-droids; they thus stand more 
perpendicularly, and consequently developc more symmetrically, whereas the ordinary colonies, being 
fixed in a more horizontal position, find it better to develope more onesidedly, with an upturned "front". 
.Among the numerous transition forms, it will here suffice to mention some specimens from 
"Thor" (65^52' N., 23°58' W.). They are very closely allied to the group of variants described as a 
distinct variety, but exhibit at the .same time several of the characteristic features of the main species. 
The stem is not quite so marked as compared with the l)ranches, albeit its darker brown colour helps 
to brmg it out; its segmentation is le.ss prominent, and the branches proceed more openly and some- 
what irregularly, with three, or more often four hydrothecce between two branches on the same side 



HYDROIDA II jjj 



of the stem, the one liydrotheca in the branch corner. Finally, the branches and the colonies are 
curved, so as to present a distincth- convex foreside: tlie branches themselves also, are not infrequentK' 
again ramified. Tlie colonies are thus typical transition forms, and as sucli occur in all shades of 
difference between the typical main form and the extreme, regnlarh' pinnate variants, we cannot 
separate the latter as a distinct species. 

Kramp (1914 p. 1053) has very appropriately characterised Dipliasid Jallax as "an atlautic 
boreal species only sporadically found in arctic regions". Its occurrence in the north Atlantic (fio-. 
LIX) shows, however, that it is still not quite universal in the boreal waters; it appears, strangely 
enough, to be very rare off the west coast of Greenland, where we should otherwise have expected to find 
it of common occurrence in the mixed compan}' of southern and northern forms found in Da\is .Strait. 
Bathymetrically, its chief occurrence falls in the middle and lower part of the littoral region, and the 
upper part of the abyssal; at times it may penetrate far down into the latter, as is shown by the list 
of finds from the "Ingolf". It is consequeuth- the more remarkable that iJipliasia fallax should seem 
to disappear at a somewhat greater distance from the coasts. A glance at the chart shows that the 
species has very rarely indeed been taken far from islands or continent, and this cannot be accidental, 
since the investigations both of the "Ingolf and later expeditions have been carried out to a verv 
great extent in the open sea within the areas in question. The exjijlanation of this must be left to 
future studies. 

Diphasia Wandeli Levinsen. 
1893 Dipluisia ]]'(ni<hli\ Levinsen, Aleduser, Ctenophorer og H\droider, p. 55, pi. 8, figs. 1—5. 

Upright pinnate colonies with pronounced dark monosiphonic main stem. The stem is divided 
by transverse nodes into short interuodia, each bearing a pair of hydrothecse placed oppositely, and a branch 
under the base of the one, turning alternately to either side of the stem. The branches are likewise 
di\'ided up into short interuodia, each having three li\'drothec;t in a wreath ; there are thus three rows 
of hydrothecse on each branch. The h\drothec£e are deepl\- embedded; the adcanline wall has a free 
distal part about one-fifth to one-fourth the length of the Indrotheca, between half and once the 
opening diameter. The opening is set almost perpendicular to the branch axis; the margin has a 
slight adcanline sinus, in which the large opercular plate is attached. 

The gonothecte arise on the branches close under the base of the hydrothecge. The males are 
reversely conical, with eight short paired spines on the distal part; the narrow distally central aperture 
has a rudimentary neck, or none at all. 

Material: 

Greenland: Davis Strait 65°22' N., 54°02' W., depth 66 fathoms |Levin sen's type specinien|. 

Diphasia Wa/ide/i appears to be a very rare species; typical three-rowed colonies have, besides 
the spot mentioned, onh' been foinid once, near Papey, East Iceland. AH the other specimens recorded 
by Ssemundsson (1902 p. 67 and 191 1 p. 97) belong properly to the above described variety of Di- 
phasia fallax. The two finds belong to the middle part of the littoral region. 



112 



HYDROIDA II 



Diphasia rosacea (Linne) L. Agassiz. 
1758 Sertularia rosacea^ Liune, Systema naturae, Ed. 10, p. 807. 

1862 Diphasia rosacea, L. Agassiz, Contributions to the natural history of the United States, vol. 4, p. 355. 
Upright colonies without distinct main stem. The colonies are irregularh- pinnate or bushily 
branched, segmented, and with a pair of oppositely placed hydrothecjE on each internodium. The 
hydrothecae are slender, almost evenly tubular, with slighth' divergent distal part. The free distal 
portion of the adcauline wall is about half the length of the hydro theca, between I'/s times and twice 
the opening diameter, rarely .somewhat shorter, down to about the same length as the opening dia- 




joo m. 600m. looom, ioocr^. 

Fig. LX. The occurrence of Diphasia rosacea in the Northern Atlantic. 
In the hatched region a common occurrence is recorded. 

meter. The opening margin has a slight adcauline sinus, in which the large opercular plate is attached. 

The gonothecse arise close under the base of the h)'drotheca;. The males are pear-shaped, 
with normally eight longitudinal ribs, each terminating in a distal short blunt point; the gonotheca 
has a central short cylindrical neck. The females are also pear-shaped, with eight long ribs, of whicli 
six terminate in as nian\- broad blades closing together over a distal brood-chamber; the two last, 
diametrically opposite ribs end in forward pointing horn-like outgrowths of varying length. 
Material : 

"Thor" 63=30' N., 20°i4' W., depth 80 metres. 

Iceland: Stykkisholm, — 30 fathoms. 

Saemundssou (1902 p. 66) also mentions specimens of this species from Ouundarfjord, Ice- 
land, but a reinvestigation of his specimens shows that the\- must be referred to Diphasia fallax. 



HYDROIDA II ji. 



Diphasia rosacea should doubtless be regarded as a southern species having a verv wide distribution 
in the southern part of the boreal area (fig. LX). It has been found at several places near Iceland, 
and is also recorded from the Faroe Islands. Round the British Isles and in the North Sea it is ver\- 
common, and very frequent between Bergen and Stat on the west coast of Norwa\-. Having also been 
found in north Norwa}' (Tananger), it will probably likewise prove to be fairly common along the 
Norwegian coast in the deeper part of the laminaria belt, which is its true home. 

Diphasia attenuata Hincks. 
1866 Scrtiilaria attoinata^ Hincks, On new Ihitish H\droida, p. 298. 
1868 Diphasia aifemiata, Hincks, A History of the British Hydroid Zoophytes, p. 247, pi. 49, fig. i. 

Upright, often brown-coloured, pinnate colonies with slightly pronounced monosiphonic stem, 
the lower part often without hydrothecce or branches, and di\-ided into internodia of irregular length; 
the upper part of the stem has alternating branches, which are in rare cases themselves secondarih- 
branched to a slight degree, and may now and again terminate in tendril-like outgrowths. The branches 
and the upper part of the stem are iudistnicth- segmented ; each internodium bears a pair of oppositely 
placed or slightly subalternating hydrothecte. Between two successive branches on the same side of 
the stem, there are as a rule three, more rareh- four Indrothecte, the lowest in the branch corner. 
The hydrothecse are large, tubular, the free distal part of the adcauline wall amounts to about half 
the length of the Indrotheca, and is somewhat more than the diameter of the opening. The hydro- 
theca is bent to an angle, so that its free part forms an angle of about 60° with the branch axis. The 
hydrotheca opening is nearly perpendicular to the branch axis; its margin has an adcauline sinus, in 
which the large opercular plate is fastened. 

The gonothecae are situate on the upper side of the branches, and proceed from close under 
the base of the hydrothecce. The male gonothecte are oval to pear-shaped, with six faint longitudinal 
ribs terminating distally in as man)- blunt points; the aperture is centrally placed on a broad distal 
cone. The female gonothecae are oblong pear-shaped, and ha\e likewise six faint longitudinal ribs, 
each with one or two markedly prominent spines on the distal part; the gonothec;e lack distal 
brood-chamber. 

Material: 

"Ingolf St. 96, 65^24' N., 29°oo' W., depth 735 fathoms, 1,2° 

- - 98, 65=38' N., 26°27' W., - 138 - 5,9» 

- - 115, 7o°5o' N., 8°29' W., - 86 — 0,1° 

- - 127, 66°33' N., 20-'o5' W., - 44 - 5,6° 

Dipliasia attoiuata belongs to the littoral region of the warm Atlantic, and penetrates at times 
even far down into the abyssal region; the species has previously been quite frequently observed in 
British waters. The finds at the threshold of Danmark Strait are therefore not surprising, but that 
from Jan Mayen is remarkable, and must doubtless be accounted for as due to larval transportation, 
possibly from the w^aters about Danmark Strait in the same way as the occurrence at the "Ingolf" 
St. 127 at the north side of Iceland. 

TIk- liigolf-E\pcdivicm. V. 7. ^5 



J J. HYDROIDA 11 



Diphasia alata Hincks. 
1855 Sertiilaria alata, Hincks, Notes on British Zoophytes, p. 127, pi. 2. 
1868 Diphasia alata, Hincks, A Histor\- of the British Hydroid Zoophytes, p. 258, pi. 48, fig. 2. 

Upright pinnate colonies with a not ver\- marked, brown, inonosiphonic stem, exceptionally 
polysiphonic in its basal part; the stem and branches are indistinctly segmented. The hydrothecse 
are arranged in opposite or subalternate pairs; they may also, in exceptional cases, be alternately set. 
On the branches, the hydrotheca; exhibit a tendency towards nnilateral arrangement on the front of 
the colony. The branches arise alternately from the stem; between two successive branches on the 
same side of the stem there are three hydrothecae, the lowest at the branch corner. The hydrothecse 
are large, bent to an angle, with a free distal portion of the adcanline wall between one-third and 
one-half the length of the hydrotheca, abont equal to the opening diameter. The abcauline wall has 
at the middle, near the bend, a prominent transverse inner rib; the angle between the branch axis 
and that of the distal part of the hydrotheca is greater than 60°. The plane of the hydrotheca aper- 
ture is almost perpendicular to the branch axis; the margin lias a deep adcanline sinus, in which the 
large opercular plate is attached. 

The gonothecie are small, almost pear-shaped, distally quadrilateral in section, with a short 
and blunt distal point in each corner, and a small round distally central opening, but no neck. The 
female gonothecse develop no brood-chamber; they are as a rule slightly asymmetrical, whereas the 
males are synnnetrical in structure. 

Material : 

"Thor" 35°57' N., 5°35' W., depth 740 metres. 

Dipliasia alata belongs to the wanner tracts of the eastern part of the Atlantic, and seems 
there to be mainly restricted to the lower part of the littoral region and the upper portion of the 
abyssal. It is a rare visitor in the northern waters, where it has been observed off the west coast of 
Scotland, at the Hebrides, Shetland, and the west coast of Norway from Jceren to a little north of 
Bergen. It has not, however, been recorded from the Faroe Islands, Iceland or Greenland. 



Geii. Dynamena (Lamouroux). 

Upright colonies with imbedded, bilaterally built liydrothecse. The hydrotheca aperture has 
two large lateral teeth, between which tliere is a large abcauline sinus and a smaller adcanline one; 
the latter is often divided into two by a slightly prominent median tooth. In each main sinus a mem- 
brane is fi.xed, so that the closing ajjparatus consists of two membranes, the abcauline with a free 
distal part. The ]Jolyp has no pronounced blind sack. 

This definition of the genus I )yiiaiiirii<i we also find indicated by Kiihn (1913 p. 252). Levin- 
sen is not disposed to consider the develo])nient of a pronounced blind sack as of any systematic 
importance (1913 p. 286,1, which view must doul)tless be accounted for by his having apparently con- 
fused this feature in the organisation with casual S-shaped hydrauth contractions. Kiihn regards the 



HYDROIDA 11 jj- 



disappearance of the blind sack as a secondary phenomenon, and keeps inainlv to the cliaracter of 
the gonangia. In this, ho\ve\-er, it is impossible to concur, as tliese organisational features are entirely 
independent one of another, and the lines of development in gonangia and jjolvps can clearh- not be 
taken as of equal significance. There is, as I have often here pointed out, no reason to reduce the 
importance of polyp development in systematics; phylogeneticalh-, it is the most valuable clue. And 
in this case, it suggests that lid formation may partly indicate converging lines, as will be seen from 
the diagram given under the heading of Sirf/tlariidcr. It is therefore likewise impossible to follow 
Levinsen in grouping Dvi/ni/uiia and Scrtularia together in one genus exclusively from the uni- 
formity of their closing apparatus. 

Dynamena pumila (Linnei Ivamourou.v. 
1758 Sertularia piii/ii/a, Linne, S>stema naturce, Ed. 10. p. 807. 
181 2 Dyniaiiiciia pniiiila. Lamouroux, Extrait d'une nremoire sur la classification des PoU'pes, p. 184. 

Upright colonies with irregular, as a rule pinnate ramification, exceptionally with an indication 
of monosiphonic main stem. The branches are secondarily ramified in irregular pinnate formation. 
The colony is divided into short internodia, each bearing a pair of hydrothecae oppositely placed. The 
h}-drotheca is deepl\- embedded ; its adcauline wall has a free distal portion about the same length as 
the opening diameter, between one-fourth and one-third the length of the hydrotheca. The opening- 
margin has two prominent lateral teeth, and in the middle of the adcauline lesser sinus is a slightl)' 
developed broad median tooth. The adcauline closing membrane has no free part; the abcauline is 
large, with a free distal part. The diaphragm almost radialh- s\'mmetrical. 

The goriothecce proceed from below the base of the hydrothecit on the one side of the branches. They 
are pear-shaped, with a ver\- short neck, and a round, s> ninietricalh' situate distal opening with oijerculum. 
Material: 

Greenland: Egedesminde 
vSukkertoppen 
Julianehaab, on Fiicns. 
Kangerdlnarsuanguak. 
Iceland: Reykjavik, on Ascophylliiiii, and Fitcus, and down to 4 fathoms depth. 
Grindavik, Bredebugt 
Grafarvogr 
Isafjord. 
The Faroe Islands: Stromo. 

Tliorsha\'n. 
I have in a former work (Broch 1910 p. 29) pointed out that Nutting's drawing of the 
gonotheca (1904 p. 27, fig. 80) is altogether misleading, presenting the impression that the acrocyst, 
as it projects from the gonotheca, must perforate the operculum. This is, however, not the case; the 
operculum opens at one side, and the acrocyst is then thrust through the opening thus made. 

Dynatncna pumila belongs to the tidal zone, and is most frequentl\- found on fncoids and the 
shallower living Lamina ria\ the species evinces a high degree of elasticitv with regard to salinity, 

15* - 



ii6 



HYDROIDA II 



and thus belongs to the hydroids found farthest up in the fjords, where the salinity is greatly reduced 
by the inflow of river water. The species has also a wide southerly distribution, and is very common 
even in the Mediterranean. It is a character form in the boreal areas (fig. LXI) where it occurs in 
quantities along the coasts. On the other hand, its occurrence in strictly arctic waters is very rare 
and sporadic. From Greenland it has been recorded at several places along the west coast, and will 
probably prove more frequent here than the data at present to hand would seem to show. 




'• *oom. ._ looom. 

Fig. LXI. The distribution of Dynamena pumila in tlie Northern Atlantic. 



Gen. Abietinaria (Kirchenpaucr). 

Upright colonies with hydrothecie having their opening horizontally or slightly obliquely set; 
the opening margin lacks distinct teeth, but has often an adcauline sinus in which the large single 
opercular plate is fixed. The polyp has a well developed abcauline blind sack. 

On comparing this definition with that given by Levinsen for the sub-genus Abietinaria 
(1913 P- 310) we at once find that there is a fundamental difference, the diagnosis here given being 
based chiefly on the organisation of the polyp. This gives us a clear mark of distinction as against 
Diphasia, and necessitates the separation of the groups as two different genera. There can be no 
doubt that i)?>/iffj/rt, as defined by Levinsen, formed a diphyletic group, and that two separate lines 
of development lead from the Sertularella to the two groups. The relation in point of opercular formation 
must here doubtless be taken as a secondary phenomenon of convergence, in comparison with the 
organisation of the polyp. 



HYDROIDA II iij 



Abietinaria abietina (Linnc) Kirchenpauer. 

1758 Sertitlaria ahirfiua, Limie, Systema iiaturce, Ed. 10, p. 808. 

1884 Abietinaria abietina, Kirchenpauer, Nordisclie Gattungen und Arteii von Sertnlariden, p. 29, 35. 

Coarsely built, pinnate colonies, the branches often secondarily branched pinnately in the same 
plane. The stem is zigzag, with paired subalternating hydrothecte in two rows, there are as a rule 
three, more rarely four hydrothecte on the stem between two sticcessive branches ou the same side, 
the lowest in the branch angle. The hydrothecte of the branches are set subalternately iu pairs, and 
in two opposite rows. The hydrothecEe are large, swollen at the lower end, narrowing upwards and 
terminating in a short .slightly outward curving neck; the aperture lies obliquely or more rarely perpendi- 
cular to the branch axis; the margin has no adcauline sinus; the opercular plate is attached adcauhnally. 
The free distal part of the adcauline wall is more than half the length of the hydrotheca, and about 
twice that of the opening diameter. The interval between two successive hydrothec:e ou the same 
side is from half to once the length of the Indrotheca, rarely a little less. The diaphragm is of dis- 
tinctly bilateral structure, with a narrow egg-shaped cleft, the longitudinal axis of which lies in the 
broad plane of the branch. 

The gonothecEe proceed from close under the basis of the hydrothecae, and are as a rule set 
on the upper side of the branch. They are oval, with a short, almost rudimentary stalk, and have a 
short, broad cylindrical neck. 

Material : 

"Thor" 65°52' N., 23°58' W., depth 62 metres 

- 62°29,5'N., 24^56' W., — 40 — 

- 64°i6' N., 22°i7' W., — 50 — 

- 64°o2' N., 22°33' W., - 34 - 

- 63=30' N., 20° 14' W., — 80 — 

- 6i°07' N., 9^30' W., - 835 - 

Greenland: Store Hellefiskebanke, off Holstensborg, depth 18—20 fathoms. 
Iceland: Bakkefjord (depth not stated) 

Seydisfjord, depth 6 fathoms 

Off Seydisfjord (depth not stated) 

Reydarfjord, depth 50 fathoms 

Ingolfshofdi 9' , miles in N. by E.V2 E. (depth not stated) 

Vestmano, depth 25 fathoms 

Reykjavik (depth not stated) 

Hvalfjord, depth 24 fathoms 

Bredebugt, 64=45,8' N., 23=55,2' W., depth 30 fathoms 

6 miles W. of Iceland, 65=00' N., 24=38' W., depth 22 fathoms 

Patreksfjord, depth 7 — 25 fathoms 

Axarfjord, — 18 — ■ 



ii8 



HYDROIDA II 



The Faroe Islands: 8—10 miles N. of the Faroe Islands (without further details) 

6 miles N. by W. of Store Kalso, depth 60 fathoms 

7 — N. by E. of Myggen^s point — 57 — 
Borona^s i^i^ miles in N. 75°W. -- 30 — 
Deep hole at north point of Nolso — 100 — 

- 150 



13 miles W. by .S. of Munken 



I have in earlier works (1908, 1909) united this species with the next, the more finely built 
form Abietmaria fiUcnla (Ellis et Solander), having overlooked the specific cliaracter which lies in the 




200 fti, ^ 6 00 m. .» .^ tooo m. 2000 m. 

Fig. LXII. The distribution of .■iS/e/tnaria nbietina in the Northern Atlantic. 
In the hatched regions a common occurrence is reported. 



peculiar diaphragm of Abietinaria abietina^ as pointed out by Levinsen (1893 p. 56). Generally speak- 
ing, the robu.ster stucture of the colonies will obviate any doubt when deahng with the last-named 
species, but this is not always the case. Occasionally, Abirlinaria abii/iiia may assume a finer struct- 
ure (of. Brocli 1908) and it was from observation of such doubtful colonies that I was led to combine 
the two species under a common name. In such dwarf colonies, however, identity ma}' easih- be deter- 
mined by examination of the diaphragm, which in Abiefinaria abietiiia is typically bilateral, whereas 
in Abietinaria Jiliaila the development is almost entireh- radially symmetrical. 

Abietinaria abietina is a circuin]wlar boreal species, capable of penetrating far into the arctic 
area, albeit its occurrence there is more sporadic. It can also move far to the south, and is found 
in the Mediterranean and at Madeira. It belongs really to the littoral region, but mav exceptionally 



HYDROIDA II uq 



penetrate down into the ab\ssal. In northern waters (fig. LXII) it is extremely frequent alon^ llie 
coast of Nor\va>', round the British Isles, at the Faroe Islands and along the east, south and west 
coasts of Iceland but very rare on the north coast of the same. Along the east coast of Greenland 
it does not appear to have been found, but it is met with again from several parts of West Green- 
land. It is remarkable that it should not be represented in the large anunnit of material collected by 
the "Ingolf" expedition, but the explanation must presumably be that the species does not often live 
far from the coasts. 

Abietinarla filicula (Ellis et Solander) Kirchen])auer. 
17S6 Scrfnlaria fiUciihi^ Ellis and vSolander, The natural history of many curious and uncommon Zoo- 
phytes, p. 57, pi. 6, figs, r, C. 
18S4 Ahictiiiarid filiculii, Kirchenpauer, Nordische Gattungen und Arten von Sertulariden, p. 29. 

Finelv built pinnate colonies, the branches often secondarih' ramified piunateh' in the same 
plane as the main colony. Stem zigzag, with paired subalternating hydrothecse in two opposite rows. 
There are as a rule three, more rarely four livdrothecte between two successive branches on the same 
side of the stem, the lowest in the branch angle. The hydrothecte of the branches also are arranged 
subalternateh' in two rows. The lu'drothecte have a swollen basal part, narrowing upwards, and with 
a slightly expanded opening margin ; the opening plane is almost perpendicular to the branch axis. 
The opening margin lacks adcauline sinus, and has a large adcaulinally fastened opercular plate. The free 
distal part of the adcauline wall about half as long as the hydrotheca, and twice the opening diameter. 
The distance between two successive hydrotheca; on the same side is about equal to the length of the 
hydrotheca. The diaphragm is almost radialh' symmetrical, with circular aperture. 

The gonothecte arise close under the base of the hydrotheca', and are as a rule set on the 
upper side of the liranches. They are oval, with rudimentary stalk, and have a broad, short cylin- 
drical neck. 

Material : 

"Thor" 65°52' N., 23"'58' W., depth 62 metres 

- 64°02' N., 22-''33' W., — 34 — 

Greenland, on ascidiae (without further details). 

Iceland: Bakkefjord, depth 25—32 fathoms 

Seydisfjord, — 6 — 38 — 

Reydarfjord, — 50 — 

Faskrudsfjord, — 20 — 50 — 

Breidalsvik, — 14 — 

Djupivogr, — 8 — 

Vestmano, — 10—15 — 

Faxebugt, — 25 — 

Stykkisholm — 30 — 

Skalanes, — 7"" 8 — 



I20 



HYDROIDA 11 



Iceland: 6 miles W. of Iceland, 65°32' N., 24°38' W., depth 25 fathoms 

Patreksfjord, depth 15 — 50 metres 

Dyrafjord, (depth not stated) 

Adalvik, ( — - — ) 
The Faroe Islands: 6i°07' N., 9°3o' W., depth 410 fathoms 

6 miles N. by W. of Store Kalso, depth 60 fathoms. 

Abietmaria fi/icula is a boreal species, rareh- penetrating into arctic waters, nor does it enter 
the warmer seas; its distribution is circnmpolar. Within the area investigated (fig. LXIII) it is freqnent 




Fig. I^XIII. The distribution of Atietinaria fiUcula in the Northern Atlantic. 
In the hatched regions the Hterature notes a common occurrence. 

off the west coast of Norway, and in the northern British waters; at the Faroe Islands it seems to 
be rare, while on the other hand it is one of the commonest species in Iceland waters, albeit lacking 
here along the north coast. About Greenland, Abie f inarm filiada is very rare, and has only been 
recorded with certainty once from the west coast, near Godthaab. It belongs to the littoral region, 
but can quite exceptionally also move down into the abyssal, as for instance west of the Faroe Islands. 



Abietinaria(?)fusca (Johnston) I^evinsen. 
1847 Sertularia fnsca^ Johnston, A history of the British Zoophytes, p. 70, fig. 11. 

1874 Thujaria salicornia, Allmann, Report on the Hydroida Porcupine, p. 473, pi. 65, fig. 3. 

1878 Selaginopsis Jusca, Mereschkowsky, New Hydroida from Ochotsk, Kamtschatka p. 436. 

1913 Abietinaria fusca, Levinsen, Systematic Studies on the Sertulariidre, p. 310. 



HYDROIDA II 



121 



Stifflv built, pinnate, dark-brown colonies with nndi\icled Ijranches. The stem, which is niono- 
siphonic, is divided up into irregular internodia, and has two single longitudinal rows of hydrothecse 
and two rows of alternating branches; there are three hydrothecce between two successive branches 
on same side of the stem, the lowest in the branch corner. The branches have two rows of very closely 
packed hydrothecse, the hydrothecce in the single longitudinal rows have their oral parts alternately 
turned to either side, making a distinct approach to quadriseiial arrangement, and the branches thus be- 
come almost quadrilateral in section. The hydrothecse are small, entirely embedded, without any free 
distal part of the adcauline wall; the opening margin forms an adcauline sinus, in which the large 
opercular plate is attached. The hydrotheca opening is comparatively very large. 




200 Tt. boom. looom. 2 00 m 

FiCT. LXIV. The occurrence of Abietinaria (^)fusca in the Northern Atlantic 
(In British waters the data are somewhat vague, but note a rather common occurrence). 

The gonotheca; are set on the upper side of the branches. They are pear-shaped, with 
short stalks. 



Material: 

-'Ingolf" St. 55 63°33' N., i5°o2' W.; depth 316 fathoms, 5,9° 
The Faroe Islands: 7 miles N. by E. of Myggenses point, depth 57 fathoms 
6 — N. by W. of Store Kalso, _ 60 — 

Deep hole at north point of Nolso, — 100 — 

16 miles E. by S. of south point of Nolso, — So- 
ft is uncertain whether this species can be allowed to retain its place in the genus Abietinaria. 

16 

Tlic Ingolf-Expedition. V. 7. 



122 HYDROIDA II 



Unfortunately, the state of the material did not permit investigation of the structure of the polyp, 
as to whether a blind sack has been developed or not; a query is therefore here appended to the 
generic name. 

The geographical data for Abicfiiiaria (?)/iisca (fig. LXI\') present a somewhat scattered im- 
pression of an atlantic species not penetrating far into the boreal waters. On the other hand, its 
marked local restriction is highly surprising; the entire area of distribution of the species, or very 
nearly so, is shown in the chart. Outside the areas marked, Abictinaria (?)fusca has hitherto been 
recorded from the east coast of England and from Bohuslan (Sweden), as also, strangely enough, in a 
single instance from the Kola I^eninsula (Jaderholm 1909 p. 95). Once also — "Ingolf" St. 55 — 
the species has been met with in the u])per part of the abyssal region; otherwise, it has only been 
taken in the lower part of the littoral. 

Gen. Sertularia (Linne). 

upright colonies with embedded, bilateral hydrothecae, the opening with two large lateral teeth, 
between which is a large abcauline and a .smaller adcauline sinus; the latter may be divided into two 
by a slightly prominent low median tooth. In each of tlie two main sinuses there is fastened a clos- 
ing membrane, so that the closing apparatus consists of a smaller adcauline membrane without free 
part, and a larger abcauline membrane with free distal part. The polyp has a well developed abcauline 
blind sack. 

The organisation of the polyp warrants the distinction here made between Sertularia and 
Dynamena. The genus Sertularia, as here laid down, forms a well-defined whole; the separation of 
the different Sertularia species, however, is an extremely difficult matter, and it is important first of 
all to take a survey of the various characters and their significance, in order to form an opinion as 
to the value of the species described from northern waters. In J ad er holm's arrangement (1909 p. 
25) we find under Thujaria the following Sertularia species: Sertularia Fahricii Levinsen, Sertularia 
robusta Clark, Sertularia plumosa Clark, Sertularia vegae Thompson, Sertularia argentea Linne, 
Sertularia cupressimi Linne, Sertularia injlata Schydlowsky, Sertularia Tolli (Jaderholm), Ser- 
tularia Thompsoni Schydlowsky, Sertularia ten era G. O. Sars, Sertularia arctica A 11 man, and Sertu- 
laria Birulce Schydlowsky; to this must Ije added the poly serial Sertularia luirabilisVeniW. There is no 
doubt that the number of .species nmst, on further investigation, be very considerably reduced. An 
examination of the variations which may occur within a single large colony will suffice to convince 
an unbiassed investigator that quite a number of the specific characters employed must be ranked 
among the more or less accidental variations, while other characters again properly belong to the 
category of developmental stage.s. It has not proved possible to procure indubitable specimens of all 
the 13 .species mentioned, but I am inclined to ascribe this in part to their lack of .solidity. 

I have already in a pre\-ious work (1909 p. 171) pointed out that of the above-named species, 
Sertularia arctica and Sertularia Thompsoni ^\^ undoubtedly synonvmous with Sertularia tenera. Jii- 
derholni's drawings (1909 pi. 9, figs. 7—9) clearly show that Sertularia vegce is synonymous with 
Sertularia robusta, to which species Sertularia plumosa sliould also ])robably be referred. We have 



HYDROIDA II J2-I 



thus brought dowu the uuniber of species to 8 or 9, which figure, as will be seen from the following, 
must be yet further reduced. Before passing on to special treatment of the different species, however, 
certain remarks as to the nature of the variations will not be out of place. 

Tlie form of the colony in all young Scrtiilaria specimens is pinnate, and with the except- 
ion of a ver}- few species such as for instance Scrtularia mirabilis, it appears to be a general rule that 
the stem sooner or later assumes a spiral coil, while at the same time the broad plane of the branches 
changes from the perpendicular to the horizontal, perpendicular to the axis of the stem. The cause of 
this spiral coiling it is difficult to determine, but the feature itself cannot be accepted as a good 
specific character (cf. Broch 1912 p. 13I More importance should be attached to the winding of the 
coil, whether right or left; the only northern species which is dextrorse is the Scrtularia Fabricii. 

A peculiarity in all spirally coiled species is the fact that their branches are more or less 
markedly dicliotomically ramified; as long as the colony still preserves its pinnate shape, this second- 
ary ramification is less pronounced, but in spirally coiled forms it is more so. 

The stem may be more or less prominent in one and the same species, now darker, now 
lighter in hue, as a rule slightly zigzag, more rarely quite straight, though this cannot be taken as a 
specific character. The distance between the branches proceeding from the stem likewise varies within 
one and the same species, and this feature has considerable influence on the habitus of the colony 
generally. The stem is in all species segmented; in those investigated, the internodia had as a rule 
one, more rarely two, and in quite exceptional cases three branches; where only one branch is present, 
it proceeds from the basal part of the internodimn. It is not altogether impossible that the frequency 
of branches from the internodia may prove of some value as a specific character. 

The hydrothecEe are subject to considerable variation within one and the same species. The 
divergent free distal part may diverge more or less from the branch, and it is somewhat different in 
the pinnate and spiral parts of the colony. In the pinnate portions, the symmetrical plane of the hy- 
drotheca always coincides with the broad plane of the branch; in the spirally coiled part, on the other 
hand, we find that the hydrothecae in most of the species tend more or less towards unilateral arrange- 
ment on the upward side of the branch. The aperture, however, varies very little indeed, and Nut- 
ting's statement (1904 p. 70) as to great variation in the character of the aperture in Scrtularia tc- 
ncra can onh- be ascribed to insufficient care in the investigation. Owing to this tendenc_\' to unilateral 
arrangement, we uormalh' find that the hydrothecse on these branches are seen in oblique projection. This 
has led numerous investigators to regard certain species, such as in particular Scrtularia argentea^ as 
furnished with as>-mmetricallv developed lateral teeth, whereas careful investigation shows that this 
is not the case. — The proportion between length of the hydrotheca and the free projecting part seems 
to furnish a useful specific character. 

The gonothecse are, as already pointed out (1909 p. 172) extremely variable in Scrtularia 

species, and their developmental stages have more than once been used as specific characters. It is 

simply astonishing to see how far from critical the investigations have often been with regard to this. 

The grown gonothecae vary greatly in one and the same species. In species where they have no 

spines, they may be round in section, or angular, with a varying number of angles; this is also noted 

by Jaderholm (1909 p. 94) but he has not noticed that one colony may have both round and angular 

l6» 



J2A. HYDROIDA II 



gonothecK at the same time. This character should therefore be used with caution. In species where 
the gonothecae are furnished with spines, the development- of the spines themselves often varies greatly 
in gonothecse which are fully developed and bear acrocysts; their number also is subject to accidental 
variation in a striking degree. All this calls for discretion in using the gonothecae as specific 
characters. 

The variational phenomena here mentioned show, that careful and critical judgement is necess- 
ary in defining Sertularia species, at the same time indicating that many of the species already estab- 
lished have little justification for their position as such. The present material does not include all 
northern species, and cannot serve as a basis for thorough revision; it will nevertheless contribute to 
the elucidation of certain synonyms. 

Sertularia cupressina Linne. 
1758 Sertularia cupressina^ Linne, Systema naturae, Ed. 10, p. 808. 
1758 Sertularia argentea^ Linne, Systema naturje, Ed. 10, p. 809. 

Upright colonies, the young ones, and the basal parts of the larger ones, to a greater or lesser extent 
pinnate, with alternating or j^artly opposite branches. The older colonies have, for a shorter or greater 
distal part, sinistrorse spirally coiled stem, so that the branches stand in a spiral. The stem is as a rule 
distinctly prominent, monosiphonic, with a branch arising basally from the internodium; more rarely, 
the latter may have two, or quite exceptionally three branches. The branches themselves are second- 
arily more or less ramified dichotomically, their broad plane is in the pinnate parts perpendicular, in 
the spiral horizontal. Between two successive branches on the same side of the stem or in the same 
sjjiral tliere are two to four, as a rule three hydrothecae, the lowest at the branch angle. The branches 
are divided up into irregular internodia witli a varying number of hydrothecae on each; the hydrothecae 
are on the lower branches oposite, or subalternately placed, and have a common plane of symmetry 
witli tlie branch; on the upper branches they are more or less turned upward towards the upper side 
of the l)rauc]i ; i. e. witli a tendency to unilateral arrangement. The depth to which they are embedded 
in the branch varies somewhat; the basal have a smaller, the distal a larger free distal part. The 
adcauline wall has a free part from one-fourth to one-half the length of the hydrotheca; from one- 
third to a little more than the diameter of the aperture. The hydrotheca has its greatest breadth 
nearly at the middle, and narrows sharply towards the aperture, less markedly towards the base. The 
opening has two strong lateral teeth of equal size. The abcauline opercular plate has a large free distal part. 

The gonothec;e proceed from the branches close under the base of the hydrothecae, and on 
tlic upiKT branches lliey are always on tlie upper side. They are pear-shaped to slender oval, and 
oval in transverse section, distally provided with one or two lateral teeth in a highly variable stage 
of development; the teetli may also be entirely lacking. Distally, they narrow evenly down to a short, 
broad opening often surrounded by a short cylindrical neck. 

Material : 

"Thor" 65°52' N., 23°58' W., depth 62 metres 
- 65°o2' N., i3°56,5'W., - 140 - 



HYDROIDA II J2- 



"Thor" 64°02' N., 22°33' W., depth 34 metres | labelled Sertularia tenera] 

— Gt;2p' n., 20=14' w., — 80 — 

Iceland: Bakkefjord, — 25—32 fathoms [labelled Serhdaria fcncra] 

Faskrudsfjord, — 20—50 — 

Vestmano — 25 — 

Hvalfjord, — 22 — [some of the specimens lalielled Sertularia 

tcnera\ 
The Faroe Islands: 6 miles N. by W. of Store Kalso, depth 60 fathoms 
7 — N. by E. of Myggenses jjoint, — 54 — 
Vestmanhavn (depth not stated) 

Glyversnass nearThorshavn ( — - — ) 
Deep hole at north point of Nolso, depth 100 fathoms 
5 miles S.S.E. of Bispen, — 50 — 

North Sea: 3V2 miles W. '/4 S. of Ksergaarde beacon, — 15 metres 

2 — N. by W. of Vederso beacon, — 18 — 20 — 

East coast of Sonthern Jntland (withont fnrther details). 

The study of the j^resent extensive material of Sertularia cupressina has shown that variations 
have played a predominant part in the separation of Sertularia species. Hincks, in his classic work 
on the British Hydroids (1868 p. 271) draws distinction between Sertularia argeiitea and Sertularia cu- 
pressina on the lines that the former has a more bushy appearance, the latter a more "spire-like 
apex", while at the same time the dark stem of the latter species contrasts strongly against the lighter 
branches. In a large material, however, both these characters are seen to be subject to great variation, 
and in both respects the two species pass gradually over one into the other. The other distinctive 
featxire is the hydrothecas, which are thus described: "The hydrothecas of the cupressina are afipressed, 
tubular, not much narrowed or divergent above, with a bilabiate mouth, while those of argetitea are 
shorter, swollen below, tapering upwards, with the aperture bent, sharply pointed at one side, and 
oblique". We need not here dwell on the general form; this is, as will be seen from the figures here 
given (fig. LXV) highly variable in one and the same branch. More weight should be attached to 
the f-act that the opening in Sertularia argentea is oblique, i. e. furnished with one more and one less 
prominent tooth. Bonne vie (1899 p. 83) also, in her determinative key, attaches principal importance 
to this feature, whereas Nutting (1904 p. 62) less happily lays stress upon the remaining features 
in the hydrotheca. Further investigation, however, soon leads to the conviction that the character is 
based upon insufficiently careful study. Owing to the strong tendency of the species towards uni- 
lateral hydrotheca arrangement on the upper branches, the hydrotheca; will here be viewed in 
oblique projection (of. fig. LXV). Consequently, the outer tooth is seen in its full length, the inner 
foreshortened in perspective. This is the cause of the oft-mentioned "asymmetry", which must conse- 
quently be abandoned as a purely fictitious character. 

Both the mentioned species are noted in the literature as having the gonothec;^ furnished 
distally with two lateral points, proceeding as outgrowths from the narrow margins of the gonotheca. 



126 



HYDROIDA II 



which is elHpsoidal in section. Even though this form may predominate in many colonies, it is 
nevertheless far from constant; a very high degree of variation may normally be observed even 
within a single colony (fig. LXV c—k). We often find, on one and the same branch, gonothecse with 
two points, others with but one, and some with none at all. (This applies, of course, only to acrocyst- 
bearing, i.e. fully developed, gonothecse; those shown were all provided with acrocysts.) Now while 
in some colonies the two-pointed gonothecse are numerically predominant, though it is extremely 
seldom that they are practicaUy supreme, this "normal" form of gonotheca is in the minority in other 
colonies, where on the contrary the great majority are of the one-pointed type; the entirely spineless 








/ 








b d It i k 

Fig. LXV. Scrtularia mpressina, 
a Distal hydrothecae of a branch of a colony from the western coast of South Jutland. — b Proximal hydrothecie from 
the same branch. c Distal hydrothecse of a branch of a colony from 6 miles N. by W. of Store Kalso. — d Proximal 
hydrothecae of the same branch. — « — g Gonothecse from the same colony as a and b. — h—k Gonothecae from the 

same colony as c and d. (X 40). 

gonotheca again is not represented to any considerable number in any colony in the material, and 
must be reckoned as an exception of more or less frequent occurrence. — The mentioned variations 
in the gonangia throw a doubtful light upon unicarinate forms such as Scrtularia Biruhr Schydlow- 
sky, where the trophosome, according to the descriptions given, does not differ from that of Scrtula- 
ria ctipressina; the species should doubtless be withdrawn, but as it is not represented in the material, 
further investigation should be made before the point is decided. 

After the investigations described, it is impossible to maintain the distinction between Scrtu- 
laria cHprcssina and Scrtularia argcntca. The distinction in question, which was originally made from 
a very restricted material, has since only been retained on the strength of superficial studies, as is 
shown by the ca.se of the asymmetrically developed teeth above mentioned. And it is just such super- 
ficial investigations which have led to this superfluity of species into which the genus is still divided. 

Scrtularia cupressina should best be characterised as a boreal species capable of penetrating 



HYDROIDA II 



127 



considerably into the arctic areas, and also sonthward into warmer seas; it is mentioned from the 
Mediterranean to Nova Zembla, but the most numerous finds have been made in the boreal region. 
The species is known from both sides of the Atlantic, and also from the Pacific, which renders its 
occurrence within the area investigated the more remarkable (fig. LXVI). It is very common in the 
British waters, and along the west coast of Norway, and is now found to l)e common also at the Fa- 
roe Islands and on the east, south and west coasts of Iceland. It has not however, yet been recorded 
from Greenland, where there would seem every reason to expect it, since it is known from the arctic 
waters off the east coast of America. The reason of this pecnliarit\" must for the present be left an 
open question. Scrtitlaria cuprcssi)ia has its chief occurrence in the upper half of the littoral region, 
and is only extremely rarely met with in the abyssal. 




zoo fti. t 00 m. 1000 (Tt. i 000 m. 

Fig. LXVI, The distribution of Scrtidaria cupressina in tlie Northern Atlantic. 
In the hatched regions a common occurrence is stated. 



Sertularia tenera G. O. Sars. 
1874 Sertularia tenera, G. O. vSars, Bidrag til Kundskaben om Norges Hydroider, p. 108, pi. 4, figs. 1—4. 
1874 Sertularia arctica, Allman, On the diagnosis of new genera and species of H\droids, p. 179. 
1884 Sertularia alhimaris, Thompson, The H\droid Zoophytes of the "Willem Barents", p. 3, pi. i, figs. 

1-3- 

nee 1877 Sertularia alhiiiiaris^ Mereschkowsky, On a new genus of Hydroids p. 228. 

18S7 Sertularia argcntea + S. Dijmplrtnr, Bergh, Goplepolyper (Hydroider) fra Kara-Havet, p. 335, pi. 

28, fig. 3. 
1899 Dyna))iena unilateralis, Bonnevie, Den norske Nordhavs-Expedition, p. 78, pi. 7, fig. 5. 
190 n Sertularia T/iompsoni, Schydlowsky, Les Hydraires de la Mer Blanche. 



128 HYDROIDA II 




The young colonies are always pinnate, the larger ones now pinnate, now with distally sinist- 
rorse stem. The stem itself is but slightly pronounced, if at all; it is monosiphonic and iudistinctly 
segmented, with almost regularly alternating branches. The branches again produce irregular, not 
infrequently alternating branchlets, which may further be tertially ramified. The pinnate portions of 
the colonies have the broad plane of the branches perpendicularly set; iu the spirally coiled ones, on 
the other hand, it is horizontal. On the same side of the stem, or in the same spiral, there are three 
very rarely two or four hydrothecse between two successive branches, the lowest 
in the branch corner. The branches are divided into irregular internodia with a 
varying number of hvdrothecse. The hydrothecse are subalternately to alternately 
placed; their plane of symmetry coincides, in the pinnate portions, with the broad 
plane of the branches, but is often mnch displaced in the spiral parts, so that 
the hydrothecse here often come very near to unilateral arrangement on the 
upper side of the branches. The hydrothecse are not very deeply imbedded, and 
have a highly diverging distal part; the free distal part of the adcauline wall 
is almost invariably more than half the length of the hydrotheca, and twice to 
three times the opening diameter. The maximal breadth is near the middle 
decreasing thence equally to either end. The aperture margin has two distinct 
somewhat rounded lateral teeth of equal size; the abcauline large lid plate has 
a large free distal part. 

Fig. LXVII. Sertularia te- ^ ^ 

wr-o. Part of a branch with a The gouothecse are attached to the branches close under tlie base of 

L Tr o i.T^-^'^'^'i ™!^' the hvdrothecre; in the spiral part always on the upper side of the branch. The 
the Kara bea, "Dijmphna. ■' ' r i j rir 

(X 40). gouothecse are oval, and round or polygonal in section, in the latter case with 

four to six, most frequently five sides; they have distally a broad round opening and an often almost 
imperceptible tubulous neck. 

Forma spitzbergehsis: large, spiral and bushy colonies with approach to unilateral arrangement 
of the hydrothecse. 

Forma sibirica: large, pinnate, slender colonies with no indication of unilateral arrangement in 
lilt- hydrothecse. 
Material : 

"Ingolf" St. 69 62°4o' N., 22° 1 7' W., depth 589 fathoms 3,9° 

"Thor" 64°i6' N., 22°i7' W., — 50 metres 

Greenland: Egedesminde, on BoUniia, — 30 — 50 fathoms 

Iceland: Hvalfjord, _ 22 — 

The Faroe Islands: 2 miles N.W. of Agraleide, depth 150 fathoms 

Kara-Sea: "Dijmphna" [labelled Sertularia argcntca. and Scrhtlaria Dij))iplunr\. 

Sertularia tenera stands clearly apart from the foregoing species, and appears to vary some- 
what less in the shape of the hydrothecse. The two geographical varieties are peculiar; the only real 
distinction lies in the habitus of the colony, and it is not altogether rare to find transition forms, 
especially in the Murman Sea. We are still, however, unaware as to what factors exert the determin- 
ative influence upon the shape of the colonies. 



HYDROIDA II 



129 



The principal difference, as compared with Scrtularia ciiprcssiyia, is apparent, even in quite 
young colonies, from the shape of the hj-drothecae. Scrtularia lenera (fig. LXVII) has larger hydro- 
thecce than the mentioned species, and the highly divergent, quite large distal free part gives the 
colonies a peculiar appearance, very suggestive of Abietinaria filicula (Ellis et Solander) with which 
also its dimensions very nearly agree. A character applicable to the larger colonies on the whole is 
the fact that the main stem in Scrtularia toicra does not exhibit any superiority in point of thick- 
ness over the branches, whereas in Scrtularia cuprcssi/ia it stands out in virtue of its greater dimens- 
ions; this feature, however, is not always absoluttly reliable. — Despite their great variability, the 
gouothecse also present certain differences as between the two species. The gonotheca; in Scrtularia 




200 rn. ».«™.__6oom -■.._._._._looo/Ti, _.. 2000m. 

Fig. LXVIII. The distribution of Sertularia tencra in the Northern Atlantic. 
In the hatched region a common occurrence is recorded. 

tencra are, even where the polygonal form is markedly prominent, never furni.shed with spines, as is 
normally the case with Scrtularia cuprcssiiia. 

J ad er holm (1909 p. 94) suggests the possibility that Dynamena imilateralis Bonnevie (1899 
p. 78) might be synonymous with Thujaria arctica (Allman). An investigation of the original specimens 
fully bears out the correctness of this supposition; the specimens are well developed and entirely 
typical colonies of Sertularia tencra forma spifzbergensis. 

Scrtularia tencra is an arctic-boreal species having its most frequent occurrence at the limit 
between the two areas; it belongs to the littoral region, and only exceptionally does it move down 
into the abyssal. The species has never before been met with at such a depth as at the "Ingolf' St. 
69, and this find must be regarded as a luere accident. Ritchie (1911 p. 218) beheves the species to 

17 

riie Ingolt-flxpeJilion. \'- 7. , ' 



I30 



HYDROIDA II 



be more common in the Scottish waters than is generally supposed from the data obtained; he con- 
siders it likely that it may have been confused with young colonies of Sertularia argcntea. This sup- 
position will probably prove correct, as the species is fairly common along the west coast of Norway, 
and penetrates right down to Bohnslan. It is also not uncommon at the F~aroe Islands and Iceland; with 
regard to the latter locality, it is scarce on the south coast, and apparently not very frequent on the 
north. From East Greenland, it is known only by a single find far to the north, whereas it has been 
met with several times in West Greenland waters. (Fig. LXVIII). 




Sertularia Fabricii Levin sen. 

1893 Serhdaria Fabricii., Levinsen, Meduser, Ctenophorer og Hydroider, p. 48, pi. 6, figs. 14—17. 

Upright colonies with not very pronounced, monosiphonic stem, the hydrothecse and branches 

forming dextrorse spirals. Of tlie basal branches, only the basal internodium is retained, the remainder 

falling away. The stem is divided into internodia, each bear- 
ing a basal branch, alternating in each of the two Indro- 
theca series; l^etween two successive branches in the same 
hydrotheca series the stem has normally three hydrothecse 
the lowest in the branch corner. The broad plane of the 
branches is horizontally set. The branches are secondarily 
ramified dichotomically, and divided into internodia of vary- 
ing length. The hydrothecte are set in two rows, sub- 
alternately or alternately placed; they are deeply imbedded 
the free part of the adcauline wall is between one-third and 
one-sixth the length of the hydrotheca, or between one-half 
a b and one whole opening diameter. The distal part of the hv- 

Fig. LXIX. Sertularia Fabricii froui Godtliaab, drotlieca diverges oulv slightly from the axis of the branch 
a Hydrothecte from the distal part of a branch. 
b Hydrotheca; from the proximal internodium of ^" the Spiral branches, the hydrothccje tend more or less 

t e same. (X 40). towards Unilateral arrangement on the upper side of the 

branch. The hydrothecse are of equal breadth in their imbedded part, and narrowing slightly in the 
free portion towards the opening; the margin of the latter has two short and broad lateral teeth; the 
abcauline opercular plate has a large free distal part. 

The gonotheca; proceed from below the base of the hydrotheca; on the upper side of the branch. 
They arc slender, reversely conical, somewhat flattened in transverse section, the narrow sides as a 
rule running out cacli into one .short, strong tooth; more rarely, one tooth — or both — may be 
lacking. The gouothcca has a broad distal aperture, furnished with a short, often rudimentary cy- 
lindrical neck. 

"Ingolf" St. 2, 63°o4' N., 9°22' W., depth 262 fathoms 5,3° 

- - 3, 63°35' N., IO-24' W., - 272 - 0,5° 

— - 4, 64°o7' N., ii°i2' W., — 237 — 2,5° 
Greenland: Store Hcllcfiskebanke, depth not stated 

Godtliaab, depth 30—40 fatlionis Levin sen's type specimens. 

Julianchaab, depth not stated 



IIYDROIDA IJ 



131 



Jan Mayen, depth 50 — 60 fathoms (East-Grceiilaiul Expedition). 
Iceland: Mouth of Berufjord, depth 41—54 fathoms. 
Kara Sea, "Dijmphna". 

Srrhihind I'tibricii is very closely related to Srrtulariu cuprrssina^ but differs ])rimaril\- in its 
dextrorse stem. Moreover, its hydrothecce are as a rule more deei)ly imbedded than in the latter 
species (fig. LXIX). Levinsen (1893 p. 48) calls attention to a peculiarity in the species, to wit, that 
the basal branches throw off their extreme parts, leaving only the proximal intcrnodium; this appears 
to be a characteristic feature in the species, the explanation of which cannot be arrived at from our 
present knowledge of its biolog)-; it gives the species a highly remarkable appearance. Another char- 




f ogo m. 



200 m. 600 m. .—._, 

Fig. LXX. Finds of Sritnlaria Fahricii ill the Northern .\tl.intic. 

acter which has been emphasised is less reliable; according to lyevinsen, the upright direction of 

the branches is 45° with the longitudinal axis of the stem; but the colonies from Jan Mayen and 

from the •'Ingolf St. 2 had branches standing out almost perpendicularly from the stem, and farther 

out even turning downwards; in these colonies also, the tendency to unilateral arrangement of tlie 

liydrothecEe is remarkably slight; despite this, and despite the fact that they arc of finer build tiian 

those from Greenland, they cannot be regarded as types of a distinct .species. 

It is interesting to note how exactly the h}-drothecas in Scrtnlaria Fahricii follow the same 

rules in tlieir variation as in Srrtularia ciiprcssina. On the proximal part of the branches, the hydro- 

thecae are far more deeply imbedded than at the extremities (fig. LXIX). The gonothecte, on the 

other hand, evince a much slighter variational tendency in the present .specimens, which rather give 

i7« 



132 



HYDROIDA II 



one the impression that only the extreme — and thus latest developed — gonothecse on the branches 
can lack one or the other of the distal spines. This is different from what we find in Scrtularia cu- 
pressma., where the variants are distributed throughout the whole of the branch, without any distinctly 
demonstrable regularity. Nutting (1904 p. 71) who mentions the fact that the gonothecEe in Seriu- 
laria Fabricii do vary, has not gone into the question of detail. 

The recent assignment of a previously undetermined specimen from the Kara vSea to Scrtularia 
Fabricii suggests that we have here a circumpolar si^ecies, capable of penetrating somewhat down into 
the boreal areas. Further investigations will probably show the species to be more common in arctic 
waters than would appear from the data on record. S( rtnlnria Fabricii doubtless belongs, strictly speak- 
ing, to the littoral region, but can, as shown by the finds at "Ingolf" St. 2, 3, and 4, also move some 
way down into the abyssal. The species has previoush- beeti recorded from Alaska and Puget Sound. 
Within the area investigated (fig. LXX) it is noted from West Greenland, Jan Mayen, and the submarine 
ridges between Iceland and the Faroe Islands, where the fauna is of a mixed character. 



Sertularia (?) tubuliformis (Marktanuer-Turnere tscher) Levinsen. 

1890 Dyiiamriia tubuliformis^ i\Iarktanner-Turneretscher, Die Hydroiden des k. k. naturhistorischen Hof- 

museums, p. 238. 

1904 Thuja ria tubuliformis, Nutting, Sertularidce, p. 70, pi. 11, figs. 1—8. 

1913 Scrtularia tubuliformis, lycvinsen. Systematic Studies on the Sertulariidae, p. 298. 

Upright pinnate colonies with alternating branches. The main stem has, on each internodium, 

on one side a branch and two hydrothecte, on the other a hydrotheca. The branch has in most cases 

minor branchlets oppositely 
])laced, and is divided by di- 
stinct segmentation into inter- 
nodia, bearing two to four, 
generally three pairs of \\\- 
(Irothecte, of which the basal 
ones are the largest, the di- 
stal being the smallest. The 
internodium as a whole tap- 
ers distally. The hydrothecre 
are set in more or less mark- 

LXXi. s^ertiiiaria tuhuiiformisirom''\\i%a\r ^\.\o. edl)' subaltematiug, often al- 
; colony showing an internodium with its ^ ., . , 

leca and the basis of two branches. '"°^^ opposite pairs, and are 

b Oonothcca. (X 40). deeply imbedded. Tlie free 

e adcaiiline wall is between one-third and one-fourth the length 
)f the hydrotheca, from half to once the opening diameter. The hydro- 
thec£e are of almost equal breadth throughout their length. The opening margin has two large lateral 
teeth, and a more or less strongly developed median tootli in the adcauline sinus. The closing appa- 
ratus consists of two membranes, of which tlu' abc;iulinc has a free distal ])art. 





nVDROIDA II j,^ 



The gonotheca; proceed from close beneath the l)ase of the hydrothecic. Thev are flattened 
pear-shaped, with a broad opening on a distally central, trnnipet-shaped neck. 

Material : 

"lugolf St. 10 64°24' N., 28^50' W., depth 7S8 fathoms, 3,5°. 

In point of habitns, this little colony much resemliles Dyinn/iriKi piiwila. I'nfortnnately, the 
state of preservation did not permit any further study of the polyps, and it is not impo.s.sible that the 
species nun- be found to lack the blind sack, in which case, of course, it must be referred to the genus 
DyuaDieiia. There is no pronounced main stem, and the colony itself rather presents the impression 
of being only a branch. In all other features however (fig. LXXI) it entirely agrees with earlier de- 
scriptions, as also with colonies from West Africa, so that its specific identity is be\ond doubt. 

Levins en (1913 p. 29S) notes that the median tooth in this species is of the same length as 
the lateral ones; this I have not found to be the case in any of the sj^ecimens I have been able to 
examine. The median tooth varies somewhat, and Levin sen's statement seems to suggest that his 
material consisted of extreme variants. 

The finding of this species in deep water so far to the north is highly interesting. In Ihe 
Atlantic, it was formerly only known from West Africa, and from the tropic-subtropical littoral region 
of America to the region of Florida. It will probably also prove to inhabit other localities in the deep 
warm atlantic waters, when sufficient investigations have been made. 

Sertularia mirabilis (Verrill) Levinsen. 
1873 Diphasia mirabilis, Verrill, Brief contributions to Zoology, p. 9. 
1893 Sertularia mirabilis, Levinsen, Meduser, Ctenophorer og H\droider, p. 49. 

Upright, robust, pinnate, colonies. The main stem slightl\- zigzag, monosiphonic, and with two 
single rows of alternately set hydrothectc. Between two successive branches on the same side of the 
stem there are three hydrothecce, the lowest in the angle of the branch. The branches have six, more 
rarely only four longitudinal rows of hydrothecae, the arrangement being ])roduced as follows: three 
(or twoj hydrothecEe are set in a wreath at the same height, and the next circle has its hydrothecse 
facing the intervals of the first. The hydrothecse are fairly deeph' imbedded in the stem and branches, 
with a free part of the adcauline wall only about half the length of the hydrotheca, or between two 
and three diameters of the opening. The opening margin has two lateral, strongly prominent teeth 
and an ahnost rudimentary median tooth in the adcauline sinus. The abcauline closing membrane 
has a free distal part. 

The gonothecK proceed from close under the ba.se of the hydrothecse on the one side of the 
branches. They are pear-shaped to oval, smooth, with a rudimentary neck and broad round aperture. 

Material: 

"Thor" 61^07' N., 9°30' W., depth 835 metres 
Greenland: Kudlisat, Disco (depth not stated) 

Store Hellefiskebanke, depth 24—32 fathoms. 



134 



HYDROIDA II 



Iceland: Adalvig (depth not stated). 
Kara Sea: "Dijmphna". 



Sertularia ii/inibilis is a circumpolar arctic species, belonging to the upper and middle parts 
of the littoral region. This being the case, it is remarkable to find it, west of the Faroe Islands, in 
the abyssal region, as taken by the "Thor" (fig. LXXII). Within the waters investigated, Scrfularia 
mirabilis is a species of rare occurrence, otherwise found once at the north-west point of Iceland, and 
high np in Davis Strait off the west coast of Greenland. 




200 RJ. __._ boom. ._._ looo m, . 

Fig. LXXII. Finds of Sci tiilaria mirabilis in the Northern .\tlantic. 



Gen. Hydrallmania (Hincks). 

Upright colonics with bilateral sessile to slightly imbedded hydrothecae. The hydrotheca aper- 
ture is furnished with two lateral teeth, between which there is a smaller abcauline and a larger ad- 
cauline sinus; median teeth lacking. In each of the two sinuses there is fastened a membrane, so 
that the closing apparatus consists of two membranes, the adcauline with a free distal part. The polyp 
has a well developed abcauline blind sack. 

The diagnosis as given coincides with Levinsen's definition (1913 p. 305); we have here 
merely added the structure of the polyj) body. — Levinsen points out that it may be considered 
doubtful whether a separation between IlydralliiKDiia and Srrf/tlaria really is altogether jnstified, and 
the observations noted in the following may to a certain degree serve to accentuate the dubiousness 



HYDROIPA II 



135 



of the point. In the northern Srrtiilaria species, we find a general tendency towards spiral arrange- 
ment of the branches, together with an often very marked approach to unilateral arrangement of 
the hydrothecae. The spirally placed branches are secondarily ramified, often dichotomically, bnt in 
Scrtularia tenera irregularly pinnately. P'rom this then, it is in reality but a short step to Ilydrall- 
rnania. And finally, there is a certain amount of variation in the Scrtulnrin species, with regard to 
proportion between the two sinuses, which in some species may be characterised as of equal size. We 
have thus, as the last and most essential distinctive feature, the fact that the adcanline closing mem- 
brane in Hyd rail Ilia )iia has a free distal part, whereas in Scrtularia^ this is reserved for the abcauline 
membrane. It may be doubtful whether these small differences should be regarded as of generic im- 
portance; for the present, however, I have found it most correct to follow Levinsen in distinguish- 
intj between the two genera. 



Hydrallmania falcata (Ivinne) Hincks. 

1758 Sertularia falcata, Linne, Systema naturae, Ed. 10, p. 810. 

1868 Hydrallmauia falcata, Hincks, A History of the Britirdi Hydroid Zooplntes, p. 273, 

Colonies with slender, .spiral, monosiphonic and segmented main stem, where 
internodium bears a branch. The branches form an open spiral about the stem, and 
are themselves regularly secondarily ramified pinnately; the main stem has a hydro- 
theca in the corner at the origin of the branch, or may in rare cases be altogether 
devoid of hydrothecse. Branches and brauchlets are segmented, the irregular internodia 
bear on the one side (the upper) a more or less close row of hydrothec^e, the opening 
part of which is turned out alternately to either side from the median plane of the 
branch. On young pinnate colonies the hydrotheCcC are imbedded, and alternately 
placed in two opposite rows on the branches, the broad plane of which stands verti- 
cally. The hydrotheca; are bottle-shaped to tubular, distally often bent, in young colo- 
nies with biserial arrangement, somewhat imbedded, in older ones with unilateral ar- 
rangement and almost sessile. The opening margin is armed with two large lateral 
teeth, the largest sinus is adcauline, and has a closing membrane with free distal part. 

The jronothecK are oval, as a rule somewhat flattened, with a short tubulous 
neck; they are quite smooth or irregular and slightly furrowed transversely. 



pi. 58. 
as a rule each 



]\Iaterial: 

"Ingolf" St. 6 63°43' N., i4°34' W., 

— - 60 65=09' N., i2°27' W., 
_ - 87 65°o2,3'N., 23°56,2W., 

— - 127 66°33' N., 2o°05' W., 



"Thor" 



66=19' N., 23°27' W., 

65=52' N., 23^58' W., 

64=16' N., 22°i7' \V.. 

64=06' N., 23=14' W., 



depth qo fathoms 7,0^^ 

— 124 - 0,9° 

— no — — 

- 44 ~ 5.6° 

— 115 — 120 metres 

- 62 — 

- 50 — 
98 - 




Kig. LXXUl. 
Ilytirallmania 
falcata from the 
Troiidhjem fjord. 
Part of a branch 
of a young, pin- 
nate colon}- of the 
Sertularia-type. 
(X 40)- 



136 



HYDROIDA II 



"Thor" 64°02' N., 22°33' W., depth 34 metres 

— 63=30' N., 20° 14' W., — 80 — 

- 6i°07' N, 9°3o' W, - 835 - 
Iceland: Reydarfjord, depth ^5—80 fathoms 

Mouth of Berufjord, — 41 — 54 — 

Vestmano, — 25 — 30 — 

Hvalfjord, — 22 — 

Bredebugt, 64°45,8' N., 23°55,2' W. depth 30 fathoms 

Stykkishohn, — 30 — 

6 miles W. of Iceland, 65°32' N., 24=38' W., depth 22 fathoms 

Talknafjord, depth 22 fathoms 

Dyrafjord, — 15 — 

0nundarfjord — 10 — 

Adalvik (depth not stated). 
The Faroe Islands: 6 miles N. by W. of Store Kalso, depth 60 fathoms 
7 — N. by E. of Myggenaes point, — 57 — 
1-2 — N.W. of Agraleide, — 150 — 

Deep hole at north point of Nolsci, — 100 — 

Sicmnndsson (1911 p. 92) briefly mentions that the branches in young colonies of Hydra 11- 
inania falcata are at times short, unbranched, and biserial, and that the same is often the case with 
the basal branches in somewhat larger colonies. Levinsen also (1913 p. 308) mentions small pinnate 
colonies of 29 mm length from Hellebsek, Denmark, but without cpioting further details as to the 
hydrothec;e. The frequent occurrence of the species in the Trondhjem Pjord has afforded an opjiort- 
unity for closer study; the colonies are often very finely built. 

Young colonies of Hydrallmaiiia falcdta \wa.\' at times even at a length of 5 cm be singly pin- 
nately branched, and it is then extremely difficult to distinguish them from Sertularia. The stem, 
which is here, of course, not yet spiral, has a hydrotheca at the base of each branch, a feature which 
is likewise common in larger colonies from the Trondhjem Fjord, and which I have found in most 
of the other colonies investigated from our seas. The hydrothecte on the branches in young colonies, 
as also those on the branches in the pinnate basal parts of older ones, are arranged in two opposite 
rows (fig. DXXIII) in such a manner that the symmetrical plane of the hydrothecse coincides with the 
vertically set broad plane of the branches; the hydrothecse on these branches are alternately set, and 
with (piite a considerable interval l)etween. The distal half, or more, of the adcauline wall is free; 
the length of the free portion is from once to twice the diameter of the opening. Quite )onng colonies 
are thus extremely liable to l)e confused with small Sn-tiilaria colonies, unless the hydrothecse are 
very carefully examined. The adcauline sinus in I/ydrailviaitia is normally deeper than the abcauline; 
the difference is, however, at times very slight, and if the closing membranes have fallen away, it is 
very difficult to identify the colonies. 

When the colonies are somewhat larger, the spiral coiHng of the stem begins to make its 



HYDROIDA II j5y 



appearance at the top. And at the same time, a marked change takes pkice in the branches, which 
now turn 90° on their axis, so that their original broad phnie becomes horizontal; further, a displace- 
ment of the hydrotheca towards the uj^jjer side of the branch also sets in, and the typical unilateral 
arrangement usual in the species now becomes apparent. Soon the bases of the hydrotheca; form a 
single row, and onl\- the oral part is turned or bent out alternately to either side of the median plane, 
as a last trace of the biserial structure. Gradually also, secondary ramification takes place, the primary 
branches throwing out secondary branchlets, directed alternately to either side in the primary broad 
plane of the branch. In the more finely built colonies, the main branch has three, or more rarelv 
four hydrothecse between two branchlets; in colonies of coarser build, on the other hand, the number 
is only exceptionally as low as three, and as a rule we find four or more lu'drothecic between the 
origins of two secondary branches. 

The features here mentioned are of importance in several respects. In the first place, the\- 
show that Hydra Ibiia Ilia colonies agree entirely in their mode of development with the remaining 
SertulariidcE having spiral stem, as far as this has been studied and described; they prove also, that 
the Hydrallmania colony, which at the first glance appears so entireh- distinct, can be easily traced 
back to the typical colony in Scrtularia tcncra or TInijaria tliuja. In the second place, the features 
in question reveal a striking resemblance between finer colonies of Hydrallnnuiia falcata and flydrall- 
majiia distans Nutting from Puget Sound ; the likeness is so great that we are tempted to note them 
down without further consideration as synonyms, or rather, to regard the specimens from Trondhjeni 
Fjord as belonging to the latter species. It would, however, be highly remarkable that this Pacific 
species should occur here and not elsewhere in the Atlantic. And closer stud\' now shows that the 
Trondhjeni Fjord type is not isolated, but is related, through every possible transition type, to the 
close and robust form which is predominant in the open sea, and which has always been taken as 
the type for HydraUiiiaitia falcata. It is interesting also to note that several colonies in the material, 
as for instance some from Berufjord, have in among the lower normal branches one or two others of 
the Scrtularia type. Elsewhere in the material we also find small colonies from several places agreeing 
with the young form from the Trondhjem Fjord, only of coarser build. : 

Nutting (1904 p. 126) notes as a distinctive character between Hydralhnania distans and Hydr- 
allmania falcata that the latter species lacks hvdrotheca on the stem at the base of the branch. 
This is, however, exceptional. The h\-drotheca on the stem at the base of the branch may at times, 
especially in older colonies, be lacking, but in most cases it is to be found, and is always present in 
the somewhat smaller colonies. Xor can the difference mentioned by Nutting as existent in the 
gonothecae be accepted as a specific character; it lies well inside the limits of variation observed in a 
single fairl}- luxuriant colony of Hydrallmania falcata. That I nevertheless refrain from definitely 
withdrawing Hydrallmania dtstans is due to the fact that m}- collections include no material of the 
species in question, and I am thus unable to determine whether possibl\- some characters not mentioned 
in Nutting's diagnosis might be found, sufficient to warrant specific distinction. The other American 
Pacific species also, Hydrallmania franciscana (Trask), calls for thorough investigation, its raison d'etre 
being likewise highly problematical. The available drawings and data for the two species are not 

enough to decide the question. 

18 

The Int^olf-Expedilion. V. -_ 



138 



HYDROIDA II 



Hydrallmania falcata has its chief occurrence in the littoral region of the boreal seas, and may 
exceptionally penetrate deeper down into the abyssal, where it has, however, once or twice been ob- 
served at 2000 metres depth. The species can move right up into arctic waters, and has even been 
met with in the Kara Sea; otherwise, its occurrence coincides with the presence of warmer currents 
in the high arctic areas. It may also penetrate some distance to the southward, as is shown by its 
more sporadic occurrence in the Bay of Biscay. In the North Atlantic also, it has been found off the 
east coast of America. It is thus the more surprising that it should never have been recorded from 
Greenland (fig. LXXIV) as it is one of the most common of all species in Iceland waters; on the west 
and east coast especially, the finds were so numerous that it was impossible to note them all on the 




. i OQO m 



Fig. LXXIV. The distribution of Hydrallmania falcata in the Northern Atlantic. 
In the hatched regions the Hterature notes a common occurrence. 

chart. On the north coast of Iceland, Hydrallmania falcaia is quite sporadic in its occurrence, and is 
not particularly numerous on the south coast. Between Iceland and the Faroe Islands, and on the 
northern side of the latter, it is again fairly numerous, while in the North Sea area and along the 
coast of Norway it appears as a character form. 



Gen. Thujaria (Fleming). 

Upright colonies with imbedded hydrothecfe. The hydrothecEC are of bilateral structure; tlie 
aperture is furnished with an abcaulinally fixed single opercular plate or membrane, attached to the margin 
of the hydrotheca, as a rule in a more or less pronounced sinus. The polyp has an abcauline strongly 
developed blind sack. 



HYDROIDA II j_Q 



Thujaria thuja (Linne) Fleming. 
1757 Sertidaria t/iiija, Linne, Systema naturae, Ed. 10, p. 809. 
1828 Thujaria thtija, Fleming, A History of British Animals, j). 545. 

Upright colonies, shaped like a bottle-brush, with dark-coloured, di.stinct monosiphonic hydro- 
caulus. The branches form an irregular, close double spiral round the indistinctly segmented stem, 
one branch to each joint. The stem has two rows of hydrothecje; there are normally three hydro- 
thecse on the stem between two successive branches in the same row, the lowest in the branch corner. 
The branches form, at their point of origin, almost a right angle with the stem, and are repeatedly 
divided dichotomously, and curve slightly upward. They are segmented, with a large and varying 
number of hydrothecae on each joint. The hydrothecae form two opposite rows on the branches; their 
plane of symmetry coincides with the broad plane of the branch, which is horizontal. The hydrothecae 
are entirely imbedded in the branches, with no free portion of the adcauline wall; they are subaltern- 
ately arranged; at the top of the branch they have two lateral teeth, but in course of growth the ad- 
cauline sinus fills up, normally altogether. The interval between two successive hydrotheca." is about 
twice the opening diameter of the h>drotheca. The operculum is formed by a round plate abcaulin- 
ally attached. 

The gonothecae are situate on the upper side of the branch, and proceeding from close under 
the base of the hydrothecae. They are oval, without ribs or wrinkles, with a short neck and broad 
round aperture. 

Material: ' ' 

"Ingolf St. 2, 63°04' N., 9=22' W., depth 262 fathoms, 5.3° 

- - 3, 63°35' N., io°24' W., - 

- - 4 64°o7' N., ii°i2' W., 

- - 15, 66°i8' N., 25°59' W., - 

- - 34, 65^17' N., 54°i7' W., - 

- - 51, 64°i5' N., i4°22' W., - 

- - 87, 65°o2,3'N., 23^56,2' W., - 

- - 95, 65''i4' N., 30^39' VV., 

- - 96, 65°24' N., 29°oo' W., 

- - 98, 65°38' N., 26°27' W., - 

- - 127, 66^33' N., 2o°05' W., - 
"Thor" 66°i9' N., 23°27' W., 

— 63°46' N., 22°56' W., — 150 — 

Greenland: Davis Strait, depth 66 — 67 fathoms (without further details) 
Iceland: Seydisfjord, — 40 — 

5 miles E. of Seydisfjord, depth 135 fathoms 
Reykjavik (depth not stated) 

6 miles W. of Iceland, 65°32' N., 24=38' W., depth 22 fathoms 

Danmark Strait 65°39' N., 28=25' W., (depth not stated) 

18* 



272 


— 


0,5^ 


237 


— 


2,5° 


330 


— 


-^o,75' 


55 


— 


— 


68 


— 


7,3: 


110 


— 


— 


752 


— 


2,1' 


735 


— 


1,2' 


138 


— 


5,9' 


44 


— 


1,6' 


"5- 


-120 m 


etres 



140 



HYDROIDA II 



Iceland: Danmark Strait 66°2o' N., 25°i2' W., deptli 96 fathoms 
Adalvik, depth 5,5 fathoms (011 roots of Laminaria). 

The Faroe Islands: 6 miles N. by W. of Store Kalso, depth 60 fathoms 
Vestmanhavn (depth not stated) 

Deep hole of north point of Nolso, deptli 100 fathoms 
16 miles E. by S. of south point of Nolso, depth 80 fathoms 
Boronses 13 miles N. 75 W., depth 30 fathoms. 

Quite young colonies of TImjaria thuja are pinnate, and very difficult to distinguish from small 
colonies of TImjaria laxa Allman. The broad plane of the branches in such specimens, up to a couple 




_ tooQ m. 



. 2 000 m. 



Fig. LXXV. The distribution of Thujana thuja in the Northern Atlantic. 
In the hatched regions a common occurrence is recorded. 

of centimetres high, is vertical, and the branches are single. Here, however, the hydrotheca at the 
tip of the branch, which is of the Srrhilaria type, will as a rule reveal the identity of the species. 
The occurrence of this type of hydrotheca in Thiijaria thuja is, as I have previously pointed out (1905) 
of considerable interest, as giving us a hint of the derivation of the Thnjaria species from St-rtidaria. 
Thujaria thuja is a boreal specie.s, capable of moving far to the south; it is said to have been 
found both off the coast of Portugal and in the Mediterranean, but is not common south of Ireland. 
On the other hand, it does not euler the purely arctic waters; it has its chief distribution in the deep 
littoral region, but may occasionally be met with in the aby.s.sal, and even deep down in the same, 
as is seen from the finds of the "Ingolf" at St. 95 and 96. In the North Atlantic (fig. LXXV) the 



HYDROIDA II 



141 



species is rare off the west coast of Greenland, and appears to be altogether lacking on the east coast. 
In Iceland waters, it is frequent on the west coast, and in Danmark Strait, and is also common on 
the east coast; common on the ridge between Iceland and the Faroe Islands, and around the latter 
Islands. In the North Sea, it is one of the most common species, and occurs also as a common form 
along the coast of Norway right up to the Nortli Cape. 




Thujaria sp. aff. hippuris A 11m an. 

From the "Ingolf St. 24 (63°o6' N., 56°oo W., depth 1199 fathoms, 2,4°) we have some colonies 

of a Thujaria, the identity of which cannot be determined with certainty. The colonies are slenderly 

pinnate, with branches ojDenly set; the stem is very slightly pronounced, and in colonies 

10 cm. high shows incipient spiral coiling at the toij; the broad plane of the branches 

here assumes a horizontal position, while elsewhere it is always vertical. The branches 

form almost a right angle with the stem. The stem has two rows of hvdrothecse, and is 

divided into internodia bearing as a rule four branches, two to either side, alternately 

placed. There are three hydrothecje between two successive branches on the same side 

of the stem, the lowest in the branch angle. The branches are irregularly segmented, 

with two to five, or rarely more, hydrothecje on the internodium. The hydrothecje are 

set in two rows on the branches; their plane of symmetry coincides with the broad plane 

of the branches; they are alternately placed on the slightly zigzag branches (and stems) 

and separated, in the same row, by intervals exceeding the length of the hydrotheca 

(fig. LXXVI). The hydrothecas are deeply imbedded, and have a short free distal j^art 

of the adcauline wall; the leuo;th of this is at the outside half the opening diameter. 

' '^^ 1 » Pig i,xxvi. 

The hydrotheca opening is round, with an even margin, and no indication of teeth or T/iujanaspafi. 
sinus; there is a large round opercular plate abcaulinalh' fixed. The colonies are nnfor- f J' u 

' .-^ I i . of a branch. 

tunately all sterile, with no indication of gonangia formation. (X4o)- 

The colonies described appear in their general features to present some considerable likeness to T/m- 
jaria liippwris K\\\T\2i\\ but are even more slender and with more widely set hydrothecse than noted for the 
species in question (cf. A 1 1 m a u 1S74, p. 473, pi. 45 fig. 2, and K r a m p 1913, JJ. 26). The shape of the colony in 
Thujaria hippuris is very nearly the same as in Thujaria thuja. The largest colonies in the material show 
that the present species would also probably be of the same form when fully grown; the pinnate arrangement 
of the colonies, and the lack of secondary ramification in the branches, can therefore only be regarded as 
juvenile characters. The slight specific differences otherwise existing in the genus Thujaria call, how- 
ever, for caution. The hydrothecx- in the colonies here concerned are not entirely imbedded, as is 
otherwise stated to be the case \\'ith Tim/aria hipfiuris, but have a very short free distal part on the 
adcauline side; there is also a wider interval between the hydrothecse in the same row, and the bran- 
ches are bent slightly zigzag fashion. These points render it somewhat doubtful whether the spe- 
cimens in question reallv belong to Thujaria hippuris, and the identity cannot be determined with 
certainty until the variational conditions of the species in question have been further elucidated. The 
enormous depth at which the colonies occur is very interesting, and will possibly serve to explain its 
extremelv slender form. 



1^2 HYDROIDA II 



Thujaria laxa All man. 
1874 Thujaria laxa, Allman, Report on the Hydroida ..... "Porcupine", p. 472, pi. 45, fig. i. 
1895 Thujaria lonchiiis, Marktanner-Turneretscher, Hydroiden von Ost Spitzbergen, p. 422. 

1903 Thujaria Hjorti. Broch, Die von dem Norwegischen Fischereidampfer "Michael Sars" ge- 

sammelten Hydroiden, p. 7, Taf. Ill, figs. 11 — 14. 

1904 Thujaria ijiimersa, Nutting, Sertularidae, p. 66, pi. 9, figs. 3 — 4. 

The upright colonies are as a rule pinnate in their lower parts, spirally curved in the upper, 
and with slender, secondarily dichotoniously ramified branches, forming an open double spiral around 
the distinct main stem, which is somewhat darker in colour. In the pinnate portion, the broad plane 
of the branches is vertical, in the spiral it is horizontal. The stem has two opposite rows of hydro- 
thecse; there are as a rule 4 or 5 hydrothecse between two successive brauches on the same side (or 
in the same spiral), the lowest at the corner of the branch. The branches form almost a right angle 
with the stem, and are very nearly straight; they are irregularly segmented with a large imniber of 
hydrothecse on each internodium. The hydrothecse are set subalternately in two rows on the bran- 
ches; their symmetrical plane coincides with the broad plane of the branch. The hydrothecae are en- 
tirely imbedded, or have a very small free distal part of the adcauline wall, never more than half the 
opening diameter. The interval between two successive hydrothecse in the same row is as a rule 
about equal to or slightly more than the opening diameter. The hydrotheca opening is round, the 
margin witliout any indication of teeth or sinus, and has a round opercular plate abcaulinally attached. 

The gonothecse are situated on the upper side of the branches close under the basis of the 
hydrothecse. They are oblong, narrow pear-shaped, the male distally cut off transversely, the female 
more rounded, without neck. 

Material : 

"Ingolf St. 3 63°35' N., 10^24' W., depth 272 fathoms 0,5° 

- - 15 66°i8' N., 25°59' W., 

- - 32 66°35' N., 56°38' W., 

- - 34 65°i7' N., 54°i7' W., 

- - 44 6i°42' N., 9=36' W., 

- - 51 64° 1 5' N., i4°22' VV., 

- - 87 65°o2,3' N., 23°56,2' W., ■ 

- - 94 64=56' N., 36°i9' W., 

- - 98 65=38' N., 26=27' W., 
Greenland: Turner Sound, 

Cape Tobin, _ 57 _ (East Greenland Expedition) 

Off Henry Land, 

Off Henry Land, 
Between the Faroe and tlie Shetland Islands, depth 255 fathoni.s. 
Kara Sea, "Dijmphna" [labelled Thujaria lonchitis and Thujaria articulatd\. 

Thujaria laxa belongs to tlie lower parts of the littoral region, and the upper part of the abys- 
sal. It is an arctic species, which has been found from Davis Strait to Tajniyr; it is also represented 



330 


— 


-^0.75 


318 


— 


3,9° 


55 


— 


— 


545 


— 


4,8° 


68 


— 


7.32' 


no 


— 


— 


204 


— 


4,1° 


13S 


— 


5,9° 


120 


— 




57 


— 


(East 


20 


— 


— 


60-: 


2CXD — 






HYDROIDA II 



143 



in the material from the cruise of tlie "Dijmplina" in the Kara Sea, but has there erronously been 
referred either to Thujaria loiicliitis or Tliiijaria articidata. From its arctic home, tlie species also 
spreads out into the boreal region (fig. LXXVII) where it has been recorded from the Faroe Islands 
and Iceland, and in Davis Strait. It will presumably also be found to occur off the coast of Norway, 
but in these waters, it has not hitherto been distinguished from Thujaria lonchifis, so that we have 
no reliable data up to the present. 




200 m. 600/n, looom. 

Fig. LXXVII. Finds of TIiKJana laxa in the Northern .Atlantic. 



Thujaria alternitheca Levinsen. 
1893 TliKJana alternitheca, Levinsen, Meduser, Ctenophorer og H\droider, p. 52 pi. 7, figs. 15—20. 

Robust, upright colonies with spiral, monosiphonic stem. The stem is divided by distinct seg- 
mentation into internodia of varying length, and has two single spiral tiers of hydrothecte; there are 
from 3 to 6 hydrothecse between two successive branches in the same spiral, the lowest in the branch 
corner. Normally, the sixth branch will be found straight above the first in the same tier. The broad plane 
of the branches is perpendicular to the a.xis of the stem (lies horizontalh') and the branches form, at 
their point of origin, almost a right angle with the stem, afterwards curving somewhat downwards; 
they are secondarily branched dichotomously, and divided into internodia with five or more pairs of 
hydrotheccc. The hydrothecEe of the branches form two very close longitudinal rows; the hydrothecse 
are closely set, each thrusting its opening part out upwards and sideways beyond the next, displaced 
alternately to either side of the median line through the base of the h}-drothecse. presenting a distinct 
approach to quadriserial arrangement. The hydrothecse are entirely imbedded in the stem and bran- 
ches, without any free distal part of the adcauline wall. The opening is circular, the margin without 
teeth or sinus, with a large round opercular plate abcaulinally attached. 



144 



HYDROIDA II 



The gonothecse are set on the upper side of the branches. They are pear-shaped, with rudi- 
mentary neck and broad aperture. 

Material : 

"Ingolf" St. 31 66°35' N., 55°54' W., depth 88 fathoms 1,6^ 
- - 34 65^17' N., 54° 1 7' W., - 55 - - 

Greenland: Davis Strait, — 100 — (without further details) [type specimen]. 

Iceland: Skagi, — 20 — [labelled Thiijaria lonchitis\ 

Dyrafjord, — 15 — 

In all probability, this species also will prove to have a pinnate development stage, like the 
other, spiral Tliiijaria species. In the arrangement of the hydrothecte, Thujaria alteriiitJieca forms a 
parallel to Abicfinaria ^] fusca (Johnston), and it is interesting here to note how the hydrothecK, 
owing to their extremely close accumulation, thrust their opening part to one side or the other from 
the base of the next following. An investigation of the tip of the branch shows that this is a secon- 
dary phenomenon. The hydrothecte are to begin with s\inmetrically situate, with their symmetrical 
plane parallel to the branch axis; only on the formation of a new distal hydrotheca is the aperture 
of the one behind it thrust out to the side. We have here, then, a typical instance of convergenc}-, 
as towards ^i5/V'//w«r/« (?)/}«<:«, which cannot be taken as evidence of closer relationship, and thus does 
not afford any justification for uniting the two species mentioned, and other multiserial forms in a 
special genus Selaginopsis\ any such would also Iiave to include species with and those without blind 
sack, which can hardly be considered permissible. 




600 m. .. .._/ooom. 

Fig. LXXVIII. Finds o£ Thuj.iria altcniithcca. 



HYDROIDA II 

H5 



Thiijaria altcniitlicca is probably an arctic species of hi<^hh- localised occurrence. It belongs 
to the deepest littoral waters. Previously, it was only known from Davis Strait, but is now found to 
occur also off tlie west coast of Iceland, where it has been confused with a form of much finer build 
Thiijaria loncliitis. 

Thujaria variabilis nov. nom. 
1899 Selagi7wpsis arctica. Bonnevie, Den Norske Nordhavs-Expedition, p. 87, pi. 6, fig. 4. 

Coarse, upright pinnate colonies with undivided branches. The stem is slightly zigzag, divided 
into internodia of irregular length, with from two to twelve regularly alternating branches and two 
single rows of hydrotheca;; the stem is not spirally coiled. The stem has from two to four, normall_\- 
three, hydrothecte between two successive branches on the .same side, the lowest in the branch angle. 
The branches have four, exceptionally two or three, rows of hydrothecse; on the four-rowed branches, 
the hydrothecse are set in opposite pairs, the symmetrical plane of the one pair being then perpendi- 
cular to that of the next; three-rowed branches are spirally coiled, two-rowed straight, with the sym- 
metrical plane of the hydrothecae vertical. The hydrothecre are broad and deeply imbedded, with a 
short, often quite insignificant free distal part of the adcauline wall, never more than a third of the 
opening diameter, or one-tenth to one-twelfth the length of the hydrotheca. The opening is round, 
with smooth margin, without teeth or sinus, and has a large opercular plate abcaulinally fixed. 

The gonotheccC are set on the upper side of the branches, and proceed from close below the 
base of the hydrothecje. The gonotheccc are inversely conical, distalh' cut off transversely, witliout neck. 

Material: 

Iceland, Reydarfjord, depth 80 fathoms (some of them labelled Thujaria lonchitis). 

A number of very fine colonies belonging to this species have been incorrectly determined 
by Ssemundsson as Thujaria loncliitis^ from which Thujaria variabilis is immediateh' distinguish- 
able by its extremely robust appearance and thick branches. The colonies are interesting in several 
respects. They show, in the first place, that aberrant branches with fewer than four hydrothecEe rows are 
by no means rare, and in the second, that the number of hydrotheca; rows on a branch may vary 
from one internodium to another. There are thus some branches which are basally quadriserial, 
distally bi- or triserial; others again are biserial, triserial or quadriserial throughout their entire length, 
or onl\- quadriserial at the extremities. This feature, then, is subject to great variation. It is also 
remarkable that biserial branches are straight, whereas the triserial, and exceptionally also the qua- 
driserial, are twisted, so that the hydrothecce here lie in very steeply ascendant spiral tiers about the 
branches. The normal quadriserial branch on the other hand, presents a compressed Staurothrca type, 
where the single hydrotheca pair is revolved as against the preceding pair, and has its plane of 
symmetry perpendicular to that of the latter; this also gives very close .spiral lines in the arrange- 
ment of the hydrothecae, as pointed out b)- previous investigators. The species, with its variations, 
gives a drastic exposure of the value attaching to the distinctive characters for the genera Stauro- 
thcca and Selaginopsis. 

It is evident from the foregoing that Selaginopsis artica Bonnevie must be classed under the 

Tlic Ingolf-Expcdition. V. 7. ^9 



j^ HYDROIDA II 



genus Thujaria, as I have already (1909 p. 222) placed it. The same genus, however, has formerly 
been made to include Serhilaria arctica Allman and Scrtularia ardica Thompson, which is incorrect 
The proper method of proceeding here will be to alter the name of the present species, as being of 
later date, and this I have accordingly done, naming it, from the variable character of the branches, 
Thujaria variabilis. 

Thujana variabilis has only occasionally been found in arctic waters near Beeren Island, at 
Spitzbergen and off the Murman Coast at 38 to 86 metres' depth. Reydarfjord thus represents the 
most southerly find, and is also, with its So fathoms, the deepest. 

Thujaria lonchitis (Ellis and Solander) Fleming. 

1786 Sertularia lofichilis, Ellis and Solander, The natural history of many curious and uncommon 

Zoophytes, p. 42. 
1828 Thujaria arficulala, Fleming, A History of british animals, p. 545. 
uec 1766 Sertularia articulata, Pallas, Elenchus Zoophytorum, p. 137. 

1847 Thujaria articulata, Johnston, A History of the British Zoophytes, p. 84, pi. 18, figs. 3—4. 
nee 1851 — — Busk, A list of Sertularian Zoophytes and Polyzoa from Port Natal, Algoa 

Bay p. 119. 

1868 — — pars, Hincks, A History of the British Hydroid Zoophytes, p. 277, pi. 60. 

1874 — — G. O. Sars, Bidrag til Kundskaben om Norges Hydroider, p. 106. 

1884 — lonchitis, Kirchenpauer, Nordische Gattungen und Arten von Sertulariden, p. 24, pi. 14, 

fig- 7- 
(neci884 — articulata, Kirchenpauer, 1. c. p. 26, pi. 14, fig. 8.) 

nee 1888 — pecfinata, Allman, "Challenger" vol. 23, p. 69, pi. 33, fig. i. 

1890 — lonchitis, Marktanner-Turneretscher, Die Hydroiden des k. k. naturhistorischen Hof- 

museums, p. 236. 

^893 — — Levinsen, Meduser, Ctenophorer og Hydroider, p. 53. 

1899 — articulata pars, Bonnevie, Den norske Nordhavs-Expedition, p. 84. 

1904 — lonchitis,^ Nutting, Sertularidae, p. 66, pi. 9, figs. 5 — 8. 

1909 — kolaensis,, Jaderholm, Northern and Arctic Invertebrates, p. 88, pi. 8, figs. 17 — 18. 

71909 — lonchitis,, Jaderholm, 1. c. p. 89, pi. 9, fig. 3. 

1909 — — Broch, Die Hydroiden der arktischen Meere, p. 174. 

The upright colonies are as a rule pinnate throughout their entire length, more rarely with a 
spirally coiled distal part of the monosiphonic stem. In the pinnate portion of the colonies, the broad 
plane of the branches is vertical, in the spiral horizontal; the branches form almost a right angle with 
the stem, which is dark in colour. The stem is segmented in its lower jDart, but in the upper, the 
segmentation becomes almost entirely effaced; the branches are subalternately to alternately set. The 
stem has two rows of h\drothectc; between two successive branches on the same side of the stem 
there will be two to three, rarely more (up to five) hydrothecte, the lowest in the angle of the branch. 
The branches are not generally ramified, but ma}- more rarely exhibit secondary dichotomous ramifi- 



HYDROIDA II J.- 



cation; they are divided into irregular inteniodia with a large and varying munber of hydrothecs on 
each. The Indrothecte are alternateh' or subalternately set in two opposite rows on the branches; their 
symmetrical plane coincides with the broad plane of the branch. The hydrothecae are deeply imbed- 
ded ; the adcauline wall has a free distal part between half and once the opening diameter or between 
one-eighth and one-fourth the length of the hydrotheca itself. The hydrotheca opening is round, the 
margin as a rule ha\ing a more or less distinct abcauline sinus, so that the hydrotlieca aperture often 
appears furnished with two sligtly prominent teeth. The distance between two hydrothecse in the 
same row is very slight, less than half the opening diameter. The operculum is formed by a large 
opercular plate abcaulinalh- attached. 

The gonothecte are set on the upper side of the branches, and proceed from close under the 
base of the hydrotheca;. They are narrow!}- jDear-shaped, with a short, often almost rudimentary cv- 
lindrical neck, and broad aperture. 

Material: 

"Ingolf St. 44 6i°42' N., 9°36' W., depth 545 fathoms, 4,8° 
- - 144 62°49' N., 7°i2' W., - 276 - 1,6° 

Greenland: Davis Strait, — 80 — (without further details). 

The synonym\- of this species is extremely difficult to determine; we are to a great extent 
forced to rely on geographical data. Kirch en pauer (1884) was really the first to point out what 
particular characters distinguish the two species which have been taken together under the name of 
Thujaria artic7ilata\ to him belongs the credit of having given the definite characterisation of that 
South Sea form for which he has — doubtless correctly — reserved the name Thujaria articulata 
(Pallas). This is specificalh' quite different from the northern species which has been given the same 
name, but which should properly be known as Thujaria lonchitis (Ellis et Solander). That the two 
have hitherto been so generally confused is due partly to the fact that writers have relied upon the 
records in the extant literature, partly to the frequent inability on the part of investigators to procure 
material of more than the one species. Thus it happens also, that even Bedot, in his brilliant work: 
"Materiaux pour servir a I'histoire des Hydroides" has committed the error of noting the two species 
as synonyms, despite the fact that the drawings given by Hincks (1868), and Allman (1888) could 
hardly be regarded as illustrating the same species. Stechow (1913 p. 152) and Broch (1914 p. 34) 
have, after further study of both species, given a closer definition of Thtjaria articulata^ from which, 
and from the descriptions given of Thn/aria lonchitis, it is evident that they differ even more than is 
usual between other species of the genus in question. 

Tlmjaria lonchitis appears to be an arctic circumpolar species, which may penetrate into the 
boreal areas. But as it has constantly been confused with related forms, especially with Thujaria 
laxa, its geographical character cannot be defined with certainty. From the list of material for 
the remaining northern species, we see that it has also in the waters here investigated constantly 
been confused with other Thujaria species, and it will therefore be most correct to leave the final 
decision as to its biogeographical position in abeyance, pending the acquisition of new and more 
reliable data. 

19* 



148 



HYDROIDA II 



Thujaria carica Lev ins en. 
1893 Thujaria carica Levinseii, Mediiser, Ctenophorer og Hydroider, appendix, pi. 7, figs. 26 — 29. 

The upright colonies are pinnate in their basal parts, spirally coiled in the distal, with bran- 
ches secondarily somewhat ramified dichotomously; the symmetrical plane of the branches is vertical 
in the pinnate parts, but horizontal in the spiral. The stem has two single, opposite longitudinal rows of 
hydrothecae; there are two to five, generally three hydrothecse between two successive branches on the 
same side of the stem, the lowest in the branch angle. The branches are divided into irregular inter- 
nodia with foiar to eight hydrothecse on each; the hydrothecEe are set subalternately in two opposite 
longitudinal rows, their plane of symmetry coinciding with the broad plane of the branch. The h\dro- 
thecas have a large free distal part; the length of the free portion of the adcauline wall exceeds the 
diameter of the opening, and is between one-third and one-half the length of the hydrotheca itself; 
the opening margin is smooth, without sinus, with a round opercular plate abcaulinally fixed. The interval 
between two hydrothecse in the same row varies somewhat, but is never less than the opening diameter. 

The gonothecse are set on the upper side of the branches in the S2)iral parts of the colonies. 
They are asymmetrical oval to pear-shaped, with a rudimentary neck and broad, round opening. 

Material : 

"Ingolf St. 143 62°58' N., 7=09' W., depth 388 fathoms, -f- 0,4° 

"Thor" 66°i9' N., .^3°i4' W., depth 115— 120 metres [labelled Tliujaria lonchitis\. 

Iceland: 32 miles vS. of »Selvogstangar, depth 170 metres. 

Kara Sea "Dijmphna" [type-specimen |. 

Thujaria. carica is an arctic species known from the waters between Spitzbergen and Beeren 
Island to the New Siberian islands; in the high arctic tracts it belongs to the upper third of the 
littoral region. South of the range mentioned, the species has hitherto only been found at the south- 
west point of Iceland, and north of the Faroe Islands, where it moves down into the abyssal region. 
ITp to now, it lias not been recorded from Greenland, and thus appears to be an easterly arctic species. 

Thujaria sp. aff. distans Fraser. 
Material : 

"Ingolf" St. 85, 63°2i' N., 25°2i' W., depth 170 fathoms 

The small Thujaria colonies from the "Ingolf" St. 85 very much resemble Thujaria carica, and 
may possibly prove to belong to that species; there are, however, certain points of difference which 
render the identity somewhat doubtful, and for the present, these colonies should doubtless be kept 
apart from Thujaria carica. It is not unlikely that they really represent a distinct species, but as the 
colonies are quite small, and without gonangia, it is very difficult to give a thorough characterisation. 

The colonies are pinnate, with simple branches. The stem, which is monosiphonic, is divided 
into irregular internodia, and lacks botli ])ranches and hydrothecte on its lower part. A couple of centi- 
metres from the Ijase, the hydrothccce begin to appear; they are set as a rule alternately in two op- 
posite longitudinal rows. The stem is slightly zigzag, and has on its upper part, besides the hydro- 
thecse mentioned, also alternating branches; the largest colony which is of quite regular build has 



HYDROIDA II 



149 



throughout three hydrothecte between the origins of two branches on the same side of the stem; in 
the two smaller colonies, on the otlier hand, the uuiuber varies from two to five, but these colonies 
are at the sauie time irregular in the wliole de\elopment of the branches in several places. The divi- 
sion of the branches into internodia is highly irregular; there ma\- be from two to 
nineteen livdrothecte on the branch internodia. The hydrothecae are set in two 
opposite rows; their symmetrical plane coincides with the broad plane of the bran- 
ches, which is everywhere vertically placed, i. e. parallel with the axis of the stem. 
The distance between two hydrothecce on the same side of the branch is very great, 
as a rule about i''2 times the length of the h\'drotheca itself. The h\drotlieca (fig. 
LXXIX) is not particularly deeply imbedded in stem or branches; the distal third 
of the adcauline wall is free; the free part of the adcauline wall is straight, or not 
infrequentlv curving .slightly upward. The opening plane of the hydrotheca is pa- 
rallel with the branch a.xis. The aperture is round, the margin exhibits indication 
of a pair of broad lateral teeth, further accentuated by the abcauline sinus in which 
the large single opercular plate is fastened. The structural character of the polyp it 
was impossible to investigate, owing to the state of preservation of the material. 

These colonies appear in the main to agree with the Pacific species Thujaria 
distans established by Fraser (1914 p. 197, pi. 32, fig. 123). There are, however, 
lacunae in Eraser's description, so the identity cannot be determined with certainty. 

Eraser's species has often secondarv dichotomous ramification of the branches; Thujaria ?,^. iiii. dista,is 

from "Ingolf St. 85. 
this must be considered as due to difference in age. On the other hand, the hydro- part of a branch. 

theca; in Tliujaria distans appear to have a larger free portion; Fraser states (X40). 

"about one-half free", and the figures appended, which are not very carefullv drawn, even show hydro- 
thecae more than half free; they give, moreover, no clear impression as to the character of the hydro- 
theca aperture, which is likewise somewhat vaguely treated in the diagnosis: "margin without distinct 
teeth but rather bilabial". Only when a conscientious description of the Pacific species is available 
will it be possible to decide whether the colonies here found in tlie Nortli Atlantic should be referred 
to the same. 




Fig. I.XXIX. 



Family series Proboscoida (Broch). 
Family Campanulariidae. 

The hydrotheca; are radially symmetrical, bell-shaped, without closing apparatus, and provided 
with a basal chamber separated off from the distal main part of the hydrotheca by a diaphragm, or 
by a simple ring-shaped thickening of the wall. The pohps can withdraw entirely into the li\dro- 
thec£E. The hydranth has a club-shaped proboscis, attached b>- a narrow base to the body of the polyp 
above the tentacle crown; the gastral endoderm is homogeneous, the stomach part not divided into 
separate regions. The colonies are stolonial or sympodial. 



J HYDROIDA II 



The diagnosis of the family as here given exclndes the two bilaterally built genera Silia/lan'n 
and Eucopella; these two genera should, i^artly on account of their being bilateral, partly also from their 
peculiar, almost leathery hydrothecse, and the small size of the latter, which can only accomodate 
the basal part of the contracted polyp, be separated off as a distinct family Siliculariidce, as I have 
pointed out already in a former work (1909). Nutting, in his latest work on Campanulanidce (1915) 
still treats the two families as one, though he gives no reason for so doing". 

The Campamtlariidcr, as here defined, make up a well marked family which can hardh- be the 
subject of much dispute; the generic sub-division of the family, however, is a highly debatable question, 
and a study of the literature thereupon affords an interesting example of the extent to which, even 
at the present da\-, it is found "convenient" (i. e. less troublesome), or "advisable" to persevere in the 
adherence to earlier tradition, or acceptance of biological phenomena, in dealing with the great group 
of the Hydroids. This is in fact the obstacle which for years has barred our progress towards an 
understanding of the group in question, its development, and the various degrees of relationship be- 
tween its subdivisions. — I have in a previous work (1909) explained at length why, in the northern 
waters, it is only permissible to recognise two genera of Caiiipamilariidcr from a phylogenetic point 
of view, to wit, Catnpanularia and Laovicdca. The description of Laomedea sargassi (Broch 1913 p. 
13) does not weaken this standpoint. Nutting, however, opines (1915 p. 24) that "while there may 
be considerable argument on theoretical grounds for such a course, it undoubtedly leads to unneces- 
sary and practically insurmountable difficulties when large numbers of species are to be handled and 
described". The correctness of this view is not immediately obvious. In the first place, it is hard to 
see whv the same characters should be easier to handle as generic than as specific distinctions; fur- 
thermore, it should be borne in mind that the pursuit of science is not an armchair occupation. In 
comparison with large genera of other groups — the pennatulid genus Pteroeides^ for instance, or the 
cirriped genus Balmnts — or even with the hydroid genus Plniiiularia, the species with which we are here 
concerned are neither more numerous nor more difficult of distinction; yet it has not hitherto been found 
necessary to break up one genus into several mereh- because it comprised a large number of species, 
or because these were difficult to distinguish one from another; any such subdivision should be based 
upon grounds of far greater scientific importance. The "insurmountable" difficulties in coimection 
with the CampanulariidcB arise from the enormous number of badly described species which have been 
established — often, moreover, on the basis of inadequate in\'estigations with regard to the study of 
variations. The result is a state of things which absolutely precludes a thorough biogeographical sur- 
vey. And this is just where the recognition of phylogeny as fundamentum divisionis would help us 
to clear matters up; from a biogeographical point of view, co-operation between phylogeny and biology 
is of the highest interest, and by giving phylogeny the precedence, with biology in the second place, 
we should obtain a sound basis and definite lines on which to set about a rational reconstruction of 
the chaos at present existing, particularh- with regard to the Caiiipa)ntlariid(e. 

We have, as a matter of fact, to face the simjile question, whether biology 
or phylogeny is to be regarded as the fundamental principle for systematics. The 
medusa system, in its present state, cannot help us in dealing with the thecaphore hydroids. The 
plasticity of the pelagic organism under the influence of physical factors in its environment is 

' Nutting still writes ''Campanularida-:". 



HYDROIDA II j-j 



enormous, and makes itself felt among the medusa; to the same degree as among other planktonic 
organisms. But the variation of single species under different conditions has been even less studied 
in the case of the medusae than in that of the polyp generation, and our ignorance as to these and 
similar phenomena has given rise to a medusa system in which phylogeny and biological con- 
vergency or divergency have been intermingled to a tangled confusion. A very fine proof of this 
is afforded by the fact that the Campamdinidce have their medusse distributed throughout almost 
all the families of Leptomeduste, and yet we cannot, from this, proceed to split up the polyp family 
in question into a similar series of new families. The question as to a division into genera on the basis of 
gonophore types should be decided by a reference to the genus Hydractinia. Following this principle 
to its logical conclusion, with the Canipai/iilan'idfc, we should have to make generic distinction be- 
tween the male and the female of Laoiiirdea flcxitosa Hincks, where, as we know, the female gono- 
phores are heteromedusoid, the males styloid. But if this is out of the question, what gonophore type 
can we consider as being generically adequate .'' The heteromedusoids are in reality the only ones 
which differ in principle from all remaining types, which, since the discovery of the reduced crypto- 
medusoid in Grai/iinaria abiethia (M. Sars) form a finite series. — In Caiupamdaria Integra (Macgilli- 
vray) \Ca)npanularia coDiprcssa Clark | we find, during one part of the breeding season free medusse, 
at another, sessile eumedusoids; there is thus no clearer limit between free medusse and sessile gono- 
phores in Caiiipajiulan'idir than in several other families. The only type of gonophore which appears 
to be of any value must then be that of Gonothyrcca. This is a highly interesting biological pheno- 
menon; phylogenetically speaking, it is a typical cryptomedusoid, (cf. Kiihn 1913 p. 1S7) differing but 
little from the gonophores in C/adocoryiic. Its systematic \-alue really lies in the fact that in certain 
forms, it is thrust out from the narrower gonotheca without breaking loose. From a biological j^oint 
of view, this is a most interesting phenomenon, and we cannot but call to mind the gonophores in 
certain Tubnlaria species, where the larvae are likewise developed in the sessile, medusa-like gono- 
phore; it shows how nature here, in another way, has arrived at the same result as in several of the 
DipJiasia species, in protecting the larva; during their period of development. Such care of the young 
occurs, of course, elsewhere in the animal kingdom, but in all other cases, it is regarded as a biological 
phenomenon, which from a phylogenetic — and thus also from a systematic — point of view is of quite 
subordinate importance. 

It may also be worth while to glance at one of the most interesting genera, Orthopyxis L. Agas- 
siz, which Nutting (1915 p. 63) again seeks to revive by the side of Clytia and Catitpanularia, all 
on the basis of the gonophores. In his generic diagnosis. Nutting refers to the Medusse of Ortho- 
pyxis as "without tentacles or manubrium", and under the heading of Orthopyxis comprcssa (I.e. p. 66) 
he states that Torrey (1902) gives for this species an illustration of "a medusa with 4 tentacles just 
escaping from the gonangium" ; under Orthopyxis evcrfa, again (1. c. p. 68) he informs us that "the 
female, at least, contain medusce which eject their ova into an acrocyst without liberating the medusse". 
Nutting has here given us a striking illustration of the value both of the genus itself and of the 
characters on which it is founded. The genus in question is really a connecting link, standing as it 
does with one foot, so to speak, in each of the other biological groups which we find represented in 
the family Cajupainilariidcc. 



j-2 HYDROIDA II 



Here, as elsewhere, when drawing the hmits of a genus, we must seek to emancipate ourselves 
from the interesting biological features of the gonophores, and have recourse to Levinsen's funda- 
mental point of view; the study of the nutritive polyps and the colonies themselves. 

We find then, that the family falls into two great groups, according to the diaphragm of the 
polyp, the arrangement being further accentuated by the two fundamentally different colony forma- 
tions, the stolonial and the sympodial. Levin sen (1893) believed to have discovered that the dia- 
phragma of the one group or genus — Cauipamilaria — was a double formation, consisting of a cen- 
tral, thin membranous diaphragm, proceeding from a circular inner thickening of the wall, the 
boundary between the main cavity of the hydrotheca and the basal chamber. A thorough investiga- 
tion of the point has convinced me (1909 p. 183) that Levinsen's conclusion must be due to his not 
having employed microtome sections; for microtome series 'reveal the fact that the "diaphragm" in 
the Campanularia group is produced by the high power of resistance against dissolvent influences 
which characterises the basal part of the supporting lamella, and that a true diaphragm, i. e. a chitin- 
ose, membranous bottom under the basal ectoderm, is altogether lacking. 

Nutting (1915 p. 9) has arrived at a different result. He supports his view upon an unpub- 
lished manuscript of his pupil, J. H. Paarmann, and on original preparations by the same hand. It 
is on Paarmann's original drawings also, that Nutting's text figures 24—44 are based. These figures 
appear to have been sketched from optical .sections, not from microtome series, and present altogether 
the impression of being not particularly reliable. Nor is this impression removed by the following 
passage quoted by Nutting from Paarmann's manuscript: "The simple diaphragm can with diffi- 
culty be seen in optical section of the hydrotheca, while the complex diaphragm is plain!)- distinguish- 
able without sectioning". Now the fact is, that the thickening of the wall in Campanularia is as a 
rule fairly easily visible, while the true diaphragm here, in such North-European species as I have 
been able to investigate, does not even show up in microtome section.— Paarmann has figured the 
"complex" diaphragm also in our European species Cajupamdaria vcrticillata (Linne). He gives, as a 
matter of fact, two figures of this, and the two are not very much alike (Nutting 1915, figs. 38 
and 43); I have not, however, succeeded in finding the membranous part of the diaphragm in Euro- 
pean specimens of the species. Paarmann's drawing also reveals a peculiarity in Laoiiiedea Jlcxjiosa 
Hincks (I.e. text figs. 9 and 26), the free margin of the diaphragm being here double, a phenomenon 
which is not discernible in Kiihn's illustration (reproduced in Nutting's text fig. 47) and is similarly 
lacking in my preparations. Details of this sort are apt to cast some doubt upon the value of Paar- 
mann's drawings. — We should note, however, that all the species in which Nutting, following 
Paarmann, finds a ".simple" diaphragm, have sympodial colonies, while among species with "complex" 
diaphragm only two species are cited: Obclia geniculata (Linne) and Obelia flabellnta Hincks, which 
have no stolonial colonics. P'rom this is might be supposed that the two species should be regarded 
as types of a drstinct genu.s, Inil this is not the case. Even in Paarmann's drawing (N uttin g 1915, 
text fig. 41) the diaphragm of Obelia flabellata is .simple; .somewhat thicker, it is true, than in most 
Laomedea .specie.s, but by no means resembling the broad wall thickening in Cainpanularia. This, 
together with the sympodial growth of the colony, places the species undoubtedl\- in the Laomedea 
group. With regard to Obelia «cuiculaia, it might be a somewhat different matter. This species 



HVDROIDA II I-. 



evinces a reniarkabh' high power of variabihty in tlie tliickness of its chitinose parts, a ]K)int which 
has been noted by Sttnmndsson (1902 p. 57) and later by myself (1909 p. 190); this variation, more- 
over, also affects the diaphragm in a pecnliar manner. In finel\- built specimens, the diaphragm is of 
the same structure as in typical Laomedea species, that is to sa>', it consists merely of a thin basal 
plate spread out below the base of the polyp; in colonies of coarser build, the chitinose thickening 
makes itself especially apparent in tlie adthecal part of tlie diaphragm, only approaching the margin 
at a much later stage, so that in longitudinal Indrotheca sections, the diaphragm appears triangular, 
supported on a broad base resting upon the hydrotheca wall. The diaphragm here, however, is in 
no wise more "complex" than Ijefore, and does not particularh' resemble the low, ring-shaped wall 
thickening in Caiiipanularia. Taking all this in connection with the sympodial development of the 
colonies, we can have no doulit we have here to deal with a topical Laomedea. 

The figure of Laomedea flexuosa mentioned above as reproduced by Nutting after Kiihn 
(1909 Taf. 17, fig. 7) shows the typical Laomedea diaphragm. A typical picture of what we find in 
Cavipamilaria is shown in fig. i, PL I. 



Gen. Campanularia (Lamarck). 

The colonies are stolonial, creeping or upright rhizocauloraes. The hydrothecic have no true 
diaphragm, but are divided by an inner thickening of the wall, more or less restricted in extent, into 
a large outer cavitv and a smaller basal. The polyp can withdraw entirely into the radially symme- 
trical hvdrotheca; it has a club-shaped proboscis and homogeneous gastral endoderm. 

Quite exceptionalh- we find, among certain species, a .slight approach to the formation of u])- 
right colonies based upon a s\^mpodial mode of ramification, so that one stalk may carr\- a single 
secondarv lateral stalk with hydrotheca. This must be regarded as the earliest indication of the typi- 
cal sympodial colonies which characterise Laomedea. The Campaimlaria species lack true diaphragm, 
but have a ring-shaped thickening of the wall (plate I fig. i) which forms the upper limit of the 
basal cavity, and furnishes, in its superior part, the point of attachment for the basal supportmg 
lamella of the polyp, which is fixed to the thickened part by a wreath of small chitinose bodies. The 
chitinose thickening ma\- be broad and not ver>- sharph' defined, or more sharply defined and nar- 
rower, in which latter case it assumes the character of an incipient diaphragm, but also in this case 
It is restricted to a low ridge. 

Campanularia volubilis (Linne) vSchweigger. 
1758 Sertiilaria volubilis, Linne, Systema naturte, Ed. 10, p. 811. 
1820 Campanularia volubilis. vSchweigger, Handbuch der Naturgeschichte, p. 425. 

Creeping colonies, from the stolons of which proceed the hydrotheca; stalks, these being as a 
rule distinctlv coiled in a spiral throughout their entire length; more rarely, the spiral may be less 
marked in certain parts, or throughout the entire length of the stalk. The stalk in^•ariably termin- 
ates in a distinct ball-shaped joint under the hydrotheca. The hydrotheca; themselves are not very 

20 

The Ingolf-F.xpedition. V. 7. 



jr^ HYDROIDA II 



large, about twice as long as broad; they are very nearly cylindrical, or somewhat tumid in the 
lower third, and with a very slightly expanded opening section; the basal third or fourth part 
of the hydrotheca tapers down, after an evenly curved transition part, rapidly to the stalk. The basal 
cavity of the hydrotheca is small, separated off from the main chamber b>- a narrow, but as a rule 
fairly prominent ring-shaped thickening of the inner wall. The transverse section of the hydrotheca 
at the aperture is circular, the opening margin has from nine to thirteen low, but generally di- 
stinct, rounded teeth. 

The gonothecEe proceed from the stolons. They are oval to bottle-shaped, with a very short, 
often ringed stalk, in the broad end, and a long and narrow, cylindrical distal neck. Thegonotheca 
is smooth, often slightly asymmetrical, rarely with curved neck. 

Material : 

"Ingolf" St. 1,3 6fs7' N., 55-^30' W., depth 35 fathoms, 0,8"^ 

- - 86 65°03,6' N., 23=47,6' W., - 76 - - 

— - 87 65°02,3' N., 23'' 56,2' W., — 110 — — 
"Thor", 65°52' N., 23°58' W., depth 62 metres. 

— 64°i6' N., 22°i7' W., — 50 — 

64=02' N., 22^33' W., - .34 - 

Greenland: Kutdlisat, Disco (depth not stated) 

Proven ( — - — ) | labelled Clytia Joh)isto)ii\ 

Store Hellefiskebanke, off Holstensborg, depth 18 — 20 fathoms 
Lille Hellefiskebanke (without further details) 
Sukkertoppen, on Boltcitia (depth not stated) 
Frederikshaab ( — - — ) 

Iceland: Seydisfjord, depth 6 fathoms 
Vestmano, — 25 — 
Hvalfjord, — 22 — 
Bredebugt, 65-17,5' N., 23°22' W., depth 7—12 fathoms 

- 64°45,8' N., 23°55,2' W., depth 30 - 

Stykkisholm, — 20 — 30 — 

6 miles W. of Iceland, (without further details) |some of them labelled Cainpaiui/an'a 

Johnsfof/i] 
Patreksfjord, depth 15—50 fathoms 
Off Dyrafjord, depth 30 fathoms. 
The Faroe Islands: 6 miles X. by W. of Store Kalso, depth 60 fathoms 

7 miles N. by K. of ^klyggenaes point, depth 57 fathoms 
Deep hole at nortli point of Nolso, depth 100 fathoms. 

Cainpanularia volubilis is a circumpolar lioreal species, with a very wide distribution in the 
arctic areas; it would perhaps be more correct to describe it as an arctic-boreal species. It does not 
penetrate very far into the warmer waters, and the records as to its occurrence in the Mediterranean 



IIYDROIDA II 



155 



would seem to be exchisivel\- due to coufusiou with Cdinptivularid Jolnistoiii Alder (cf. Hroch 1912 p. 
51). The species belougs cliiefK' to the littoral region, es])ecialh- its upper half, but may quite excep- 
tionalh' penetrate some way down into the abyssal. Within the waters investigated, Campaimlaria 
vohibilis is one of the most common Caiiipa)iulariid<r\ it is but rarel\- found, however, out in the open 
sea regions, which must probabh' be understood as standing in connection with its bathymetrical 
character (fig. LXXX). The species is not uncommon in West Greenland waters, but on the east 




200 m. __._---6oom, _._._..».«looom. 2000 m. 

Fi"-. LXXX. The distribution of Campannlan'a volubilis 111 the Northern Atlantic. 
In the hatched re.a:ioii,s a common although scattered occurrence is stated. 

coast of Greenland it has only been met with north of 76". Of the Iceland coasts, it seems to prefer 
the east and west; it is less frecpient at the Faroe Islands, and is stated as being of common, though 
scattered occurrence round the British Isles and off the west coast of Norway. 



Campanularia verticillata (Linne) Lamarck. 
1758 Sertularia verticillata, Liune, Systema naturre, Ed. 10, p. 811. 
1816 Campanularia verticillata. Lamarck, Histoire uaturelle. vol. 2, p. 113. 
nee. 1907 Campauiilaria verticillata. Hickson and Graveh', National Antarctic Expedition, p. 23. 

Upright, stiffly built rhizocaulomes, from the numerous tubes of which the hydrotheca stalks 
proceed, arranged approximately in wreaths. The stalks exhibit distinct rings, whicli are most pronoun- 
ced near the origin, and nearer the hydrotheca; the stalk always terminates under the hydrotheca m 
a ball-shaped joint; the middle of the stalk is generalh' smooth. The hydrotheca is about twice as 



156 



HYDROIDA II 



long as broad, cylindrical, with a curved basal part tapering sharply towards the stalk. The hydro- 
theca is circular in transverse section near the aperture; the opening margin is furnished with ten to 
fourteen low, rounded teeth. The basal cavity of the hydrotheca is small; the limit between this and 
the large main chamber is formed by a low, but often fairly narrow and sharply defined ring-shaped 
inner thickening of the wall. 

The gonothecse proceed from the tubes of the rhizocaulome, and are attached to the same by 
an almost rudimentary stalk. They are bottle-shaped, with a broadly rounded basal part, and a short, 
rather narrow, tubulous neck, as a rule curved or somewhat asymmetrical. 

Material : 

"Ingolf St. 127 66°33' N., 20°05' W., depth 44 fathojns, 5,6°. 
"Thor" 64°02' N., 22°33' W., depth 34 metres 

— 63°3o' N., 2o°i4' W., — 80 — 
Greenland: Davis Strait, depth 80 fathoms (without further details) 

_ _ , 67°24' N., 55''39' W. (depth not stated). 
Iceland: Vestmano, depth 49 fathoms. 
The Faroe Islands: 6 miles N. by W. of Store Kalso, depth 60 fathoms 

Glyversnses near Thorshavn, together with red algee (depth not stated). 

Caiiipamtlaria vrrticilhita is a circumpolar arctic-boreal species, penetrating only Slightly to the 
-south, but still met with off the coast of France. The statements in one or two recent works, how- 



60 



40 






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200 m. 600 m, \oQQ m. . 2 oao m. 

Fig. LXXXI. Tile distribution of Campannlnria vcrticillata in the northern Atlantic. 
Ill the hatched regions the literature notes a common occurrence. 



HVDROIDA II jj.- 



ever, (Kramp 1914 p. 1069; Nutting 1915 p. 31) as to its also belonging to the antarctic region, 
are incorrect. Hicksou and Gravely (1907 p. 23) mention, it is true, Campanularia verticillata var. 
grandis from ]\Ic Murdo Bay, but what they found there was, as Vanhoffen has pointed out (1909 
p. 294) really the altogether different antarctic species Caiiipanularia lobala Vanhoffen, wliich has but 
one character in common with our northern Campanularia verticillata: the fact that the colonies are 
as in the latter, rhizocaulomes. Campanularia verticillata is thus not a bipolar species. — Campa?in- 
laria verticillata belongs to the middle parts of the littoral region, but may also be met with in quite 
shallow water; not infreqnenth- also, it ma\- penetrate down into the abyssal region, where it has even 
been found at no less than 600 metres' depth. Its distribution in our seas (fig. LXXXI) shows that 
it is restricted to the coastal waters. The species is not uncommon on the west coast of Greenland ; 
on the east coast, however, it has only once been taken north of 76°. In Iceland waters, it seems to 
keep chiefly to the southern coast: it is also found scattered about the Faroe Islands. Round the 
British Isles and off the coast of Norwa\' it is of verv common occurrence. 



Campanularia groenlandica Levin sen. 
1893 Campanularia groenhindiea, Levinsen, IMeduser, Ctenophorer og Hydroider p. 26 pi. 5 figs. 10 — 12. 

Creeping colonies, from the stolons of which the hydrotheca stalks proceed; the latter may be 
ringed throughout their entire length, or, more commonly, having a smooth middle part; more rarely, 
tlie rings are found to be almost entirely lacking. The stalk invariabl\- terminates under the hydro- 
theca in a ball-shaped joint. The large hydrothecte are about i' , times as long as broad, typically 
bell-shaped, with gently curving sides, the greatest bend occurring in the basal third to fourth of the 
hydrotheca. At the aperture, the hydrotheca is polygonal in transverse section, with from ten to fifteen, 
generallv twelve or thirteen straight or slightly concave sides, each running out at the opening into 
a markedly prominent rounded tooth. In the intervals between the teeth, the margin is slightly curved 
outwards. The basal chamber is quite low, and bounded at the top by a faintly developed narrow 
ring-shaped inner thickening of the hydrotheca wall. 

The gonotheca; proceed from the stolons, and are attached to the same by a rudimentary stalk. 
They are elongated oval or bottle-shaped, with a fairly long, narrowly cylindrical neck; they are 
smooth or indistinctly wrinkled, generally .somewhat asymmetrical; the neck is straight or more or 
less curved. 

Material: 

"Ingolf St. 31 66°35' N' 55°54' W., depth 88 fathoms 1,6'' 

- - 34 65°i7' N., 54°i7' W., - 55 

- - 87 65°02,3' N., 23^56,2' W., - 110 - - 

Greenland: Davis vStrait — 80 — (without further details) | [ Levi n sen's 

Store Hellefiskebanke ( - - - ) ' type-specimens| 

Iceland: 64°i7,5' N., i4'44' W., — 75 metres 5,12° 

Bredebugt, 65°45,8' N., 23°55,2' W., depth 30 fathoms. 



HYDROIDA II 



Campamdaria groenlandica is a circunipolar arctic species belonging to the littoral region. It 
is undoubtedly of more common occurrence tlian the data to hand appear to show; this is probably 
owing to its having been confused with Cainpauiilaria Hincksii Alder, the prismatic hydrothec£e of 
which present a certain likeness to those of Campaintlaria groenlandica. That such confusion has taken 
place as far as the Norwegian waters are concerned would seem to be beyond doubt; we find here, 
that Campaniilaria groenlandica moves southward at an\- rate as far as Trondhjem Fjord (fig. LXXXII). 
The species has once or twice been encountered off the east and west coasts of Iceland ; on the east 
coast of Greenland it has not been met with south of 76°, but along the whole of the west coast, 
which is its classical ground, it is fairlv common, occurring often in company with Campamdaria 
volubilis. 




I-ig. LXXXII. Tinds of Campamtlaria groenlandica in the Northern Atlantic. 



Campanularia speciosa Clark. 

1876 Cainpauitlaria speciosa, Clark, Report on the Hydroids Alaska, p. 214, pi. 9, fig. 11. 

1913 Cawpaniilaria viao,/i/ica, Fraser, Hxdrnids from \'aucou\-er Island and Nova Scotia, p. 164, pi. 

II, figs. 1 — 3. 

Creeping colonies, from the stolons of which proceed shorter or longer, irregularh- wrinkled 
or ringed stalks, terminating under the hydrotheca itself in a ball-shaped joint. The large Indrothecce 
are swollen at the bottom, with gently curving sides, narrowing upward.s, but rapidly expandinc 
distally near the aperture, so that the opening margin curves strouglv outwards. Tht 



le margin is 



HVDROIDA II jcQ 



furnished with seven to ten broad, slightly prominent teeth. The opening part curving more strongly out 
between the teeth, we have a broad furrow running from the highest point of the teeth and continuing 
some way down the hydrotheca, where it disappears. The longitudinal axis of the h\-drotheca: is often 
somewhat curved. The basal cavity is very small, bounded at the top b}' a sharjjly defined, fairly 
prominent ring-shaped thickening of the inner wall. 

The gonothecse are attached to the stolons by a short, often rudimentary stalk. Thev are egg- 
shaped to oval, attached to the stalk by their broad end, and running out distally to a fairly long, 
narrow cylindrical neck. The gonothecte are often .slightly bent, and faintly and irregularly wrinkled 
transversely. 

Material: 

Greenland : Store Hellefiskebanke, depth 24 fathoms. 

The above-noted synon^'m Campamdaria magiiffica Fraser (1917 p. 164, pi. 11. figs. 1—3) ought 
not really to require any further explanation. Fraser (1917 pi. 11, fig. 4) figures for purposes of com- 
parison a gonotheca of Caiiipamtlaria spcciosa from Alaska; this is, like the one shown by Levin- 
sen (1893 pi. 5, fig. 7) a developmental stage, only a little younger still. I have previously described 
the fulh' developed gonotheca after speciujens from the Kara Sea (1912 p. iS fig. 3); the conformity 
with Fraser's pi. 11 fig. 2 is e\ideiit. The other distinctive characters noted by Fraser are void of 
all significance, as will be seen from a somewhat richer material of the species. 

CatiipaHidaria spcciosa is a panarctic species, belonging to the shallower parts of the littoral 
region. Within the areas investigated, it is onl\- known from West Greenland, where its most south- 
erlv occurrence was noted on the Store Hellefiskebanke. 



Campanularia Integra Mac Gillivray. 
1842 Campnnularia Integra^ Mac Gillivray, Catalogue of the marine Zooph\'tes of the neighbourhood 

of Aberdeen, p. 465. 
1853 — caliculafa, Hincks, Further notes on British Zoophytes, p. 178, pi. 5, fig. B. 

1876 — coDipressa, Clark, Report on the Hydroids .... Ala.ska, p. 214, pi. 8, figs. 5—6. 

1901 — Rittcri, Nutting, Papers from the Harriman Alaska Expedition, p. 171, pi. 17, fig. 5. 

1915 — — Nutting, Campanularidae, p. 35, pi 2, fig. 2. 

1915 — Integra, Nutting, 1. c. p. n, pi. 1, fig. 7, pi. 2, fig. 3. 

1915 Ortliopyxis caliculafa, Nutting, 1. c. p. 64, pi. 15, fig. 4. 
1915 — coiiiprcssa. Nutting, I.e. p. 65, pi. 15, figs. 5—10. 

Creeping colonies, from the stolons of which proceed hydrotheca stalks, smooth, or more or 
less distinctly ringed or spirally coiled, especially near their origin, and close under the hydrotheca; 
the stalk here always terminates in a ball-shaped joint. The hydrothecee are large, inverseh- conical 
to nearly cylindrical; the conical ones taper gently down throughout their whole length towards the 
stalk; otherwise, the hydrothecie are rounded smoothly off at their basal part; every pos.sible kind of 
intermediate form ma^■ be found. The hvdrotheca margin is smooth, with no indication of teeth, 



j5o hydroida II 



often curving slighth' outward. Tlie basal chamber is well developed, and bounded at the top by a 
more or less pronounced ring-shaped thickening of the wall, often with a fairly thick base. 

The gonothecae are attached to the stolons by a short, generally rudimentary stalk. Tlie\- are 
oblong oval to cylindrical; the wall is often furnished with oblique furrows forming a spiral, but may 
as often as not be cpiite smooth; all intermediate forms and types occur in one and the same colony. 
The gonophores are eumedusoid and sessile, or break loose during a part of the breeding season as 
defective medusas (/Igasfra). 

Material : 

"Ingolf St. 34, 65"i7' N., 54°i7' W.; depth 55 fathoms 

- -127, 66°33' N., 2o°o5' W.; - 44 - 4,6° 

"Thor" 64°02' N., 22°33' W.; — 34 metres 

Greenland: Godhavn (depth not stated) 

Jakobshavn ( — - — ) 
Egedesminde ( — - — ) 

Store Hellefiskebanke, off Holstensborg (depth not stated) 
Davis Strait, depth 100 fathoms (without further details) 
Sukkertoppen on alg:e (depth not stated) 
Godthaab ( — - — ) 

Iceland: Bakkefjord, depth 10 fathoms 
Vopnafjord, on littoral algce 
Seydisfjord, dej)tli 6 fathoms 
Vestmano, on littoral algae 
Reykjavik, depth 2 — 3 fathoms 
10 miles W. of Akranes, depth 26 fathoms 
Keflavik, on littoral algae 
Bredebugt, 65°i7,5' N., 23^32' W., depth 7—12 fathoms 

— 65" 18,5' N., 23°02' \V., — Cj — 12 — 

Stykkisholm — 30 — 

The Faroe Islands: vSvino, on laminanans, depth 60 fathoms. 

The synonynn- of this species should be clear enough after the investigations which have been 
made by Levinsen (1893) Kramp (1911) and myself (1909); nevertheless we find, that Nutting 
(1915) again distributes the species among no fewer than four, and even places these in two different 
genera. With regard to the transition stages between Campamdaria Integra and Orthopyxis caliculata, 
we find the following (1915 p. 34) "Broch . . . says that the gonangia of the two species intergrade, but 
I have seen no instance of the kind, and, as the two may occur together, a very careful dissection 
would be necessary to place the matter be\ond doubt". It is precisely such careful dissections which 
have convinced Levinsen and myself that all transition forms and \-ariants do occur on the same 
stolons; we have only to regret that Nutting has not been equally conscientious in his methods 
of work. 



HYDROIDA II 



l6l 



It might be supposed that Nutting's material of Campanularia intcgra was restricted to 
some few colonies from scattered localities, each representing accidental variant groups, since the 
species is distributed under four separate names. The above indication of the methods pursued, how- 
ever, taken together with the following statement, will give a good idea as to the cause (Nutting 
1915 P- 34): "It should be understood moreover, that the present writer repudiates the idea that occas- 
ional intergradatiou in these low forms is sufficient ground for uniting species that are usually and 
perfectly distinguishable". 

Giard (1899) lias pointed out that the gonophores in Campanularia integra break away during 




200 m. .r«__ 600 m. .— . ...1000 ^. .._.. . 2000 m. 

Fig. LXXXIII. Distribution of Campanularia integra in the Northern Atlantic. 
In the hatched regions a common occurrence is stated. 

part of the breeding season as defective medusce, but are otherwise ses.sile. The correctness of this 
observation has been doubted, but is further confirmed through the investigations of Behncr (1914). 
This writer refers to the species investigated as Canipaiiu/an'a compressa Clark, but it is impossible 
to discern wherein the difference between that species and Cainpaini-laria integra should be supposed 
to lie. The species thus stands with one foot in each of the two old genera Campa^iularia and Clytia. 
Nutting grasps at this as a welcome opportunity of separating off yet another genus, 0;-/jiyV)/.rz>, and 
believes to have rendered the system clearer and easier to deal with thereby. 

Campanularia Integra is a purely cosmopolitan species, which prefers the upper part of the 
littoral region, but may nevertheless occassionally be met with a good way down in the abyssal, 
exhibiting thus, apart from its enormous power of variation, a high degree of elasticity with regard 
to temperature. In respect of salinity, on the other hand, it appears to be more susceptible, and does 

The Ingolf-Expedition. V. 7. 



l62 HYDROIDA II 



not move far up into the fjord waters. This may possibly also account for the distribution of the 
species within the area investigated (fig. LXXXIII). Cavipanularia integra is very common along the 
west coast of Greenland, but lacking on the east coast south of 76° N., according to what we know 
up to the present. The remarkable paucity of hydroids — arctic or boreal, — along this coast can- 
not be explained as due exclusively to temperature conditions, but must doubtless, judging from Caiii- 
panularia integra^ be partly occasioned by an accumulation of the fresh glacier water along the shore 
in contrast to the west coast, where warmer atlautic currents occasion a livelier interchange of water 
supply. A further peculiarity appears to lie in the scantiness of the species at the Faroe Islands; 
this, however, may possibly be accounted for by the fact that zoological bottom investigations have 
for the most part been made at greater depths than those at which the species chiefly lives in 
these waters. 

Campanularia Hincksii Alder. 
1856 Cai/ipami/arm Hincksii, Alder, A notice of some new genera and species, p. 360 pi. 13, fig. 9. 

Creeping colonies, from the stolons of which proceed long hydrotheca stalks, more or less 
distinctly ringed above their point of origin and under the hydrotheca; the stalk terminates below 
the hydrotheca in a ball-shaped joint. The hydrothecce are very nearly cylindrical, with an evenly 
curving, rapid transition from the bottom to the stalk. In transverse section, the hydrotheca is poly- 
gonal, with eight to fourteen straight sides, each running out at the oi^ening into a strong tooth, 
transversely cut off; the teeth may also at times exhibit a slight median incision. The basal cavity is 
small, bounded at the top by a sharply defined low and narrow ring-shaped thickening of the 
inner wall. 

The gonothecse are attached directly or by a rudimentary stalk to the stolons. They are 
elongated egg-shaped, broadest about the lower third, cut off trausversel\- at the distal part, and with 
more or less prominent transverse furrows. 

Material : 

Iceland: Vestmano, deptli 28 fathoms. 

North Sea: 57°o7' N., 2°4o' E., depth 37 fathoms. 

Stemundsson (1911 p. 77) mentions under this species an instance in which an approach to 
rhizocaulome formation was found, giving rise to a stem 1 cm high, whereby the colony assumed a 
considerable resemblance to Campamdaria vcrticillata. 

Canipanularia Hincksii is a southern species doubtless more rare in northern waters than would 
appear from the records extant. It lias frequently been confused with Campanularia grocnlandica, which 
it somewhat resembles in a sterile state. Its occurrence in arctic waters is in reality very doubtful, 
and we must await further data before we can decide its biogeographical character with any certainty. 



HVDROIDA II 



163 



Campanularia Johnstoni Alder. 
1856 Caiiipa/ni/iin'ii johnstoni, Alder, A notice of some new genera and species, p. 359, pi. 13, fig. 8. 
i860 Clytia bicopliora, L. Agassiz, Contributions to the natural history of the United States, Second 

Monogr. vol. 4, p. 304, pi. 29, figs. 6—9. 
1868 — jo/iiistoin\ Hincks, A History of the British Hydroid Zoophytes, p. 143, pi. 24, fig. i. 

Creeping colonies, from the stolons of which proceed fairly long hydrotheca stalks, ringed at 
the base and below the hydrothecte, the middle part generally smooth. The stalk terminates below 
the hydrotheca in a ball-shaped joint. The hydrothecte are of varying .size, from twice to 2' .. times 
as long as broad, cylindrical or inversely conical, with gentl\- cur\iug basal part. 'I'he ludrotheca is 
circular in section at the aperture; the opening margin is furnished witli ten to sixteen sharp or point- 
edly rounded, highly prominent teeth. The basal cavity is rather large, terminating at the top in a 
narrow, sharply defined ring-shaped thickening of the inner wall, which in fineh' built specimens often 
presents the appearance of a ver\- low diaphragm. 

The gonotheciE are attached to the stolons by a .short, ringed stalk. They are cylindrical, 
narrowing sharply at the base, cut off transversely at the distal end, and have deep transverse furrows 
generally forming a slowh' ascending, close spiral. The gonoi^hores develope into free medusse (Clytia). 

Material: ' '"" ' """"' ----- - . -•- 

Iceland: Vestmano, depth 25 fathoms. 

The Faroe Islands: 6 miles N. by W. of Store Kalso, depth 60 fathoms 

deep hole at north point of Nolso, — 100 — 

6j°4o' N., 7°4o' W., - 135 - 

North Sea: 57°o7' N., 2°4o' E., 1 r.:..' -..:ri^\r^c — 37 - 

Nutting (1915 p. 54) endeavours once more to di\ide Campanularia [ohnstoni from Clytia 
bicofihora, partly on the ground that the latter species is said to possess a diaphragm, partly because 
it is finer in the chitinose parts. The thinner chitinose formations involve, in Campanularia /olinstoni 
as in other species, a more restricted thickening of the wall, so that there may often be some con- 
siderable resemblance to a low diaphragm, and hydrothecse of this type always exhibit a marked ten- 
dency to wrinkle up on preservation. There is, however, no reason to take all this as furnishing 
sound specific characters, and we also find that all other investigators agree in uniting the two spe- 
cies as Campanularia /ohnstoni. This is doubtless correct. 

Cumpamclaria Johnstoni is a widely distributed southern form, which thri\es to a marked degree 
upon Sargassum; it can, however, penetrate quite far down within the littoral region. In the northern 
seas (fig. LXXXIV) it appears as a southern visitor, found once so far to the north as Hammerfest 
on the coast of Norway, but otherwise only once met with at Bergen. In the North Sea it is more 
common, as also at the Faroe Islands; it is of ver}' frequent occurrence round the British Isle.s, but 
rare in Iceland waters. Its distribution is that of a species typically belonging to the warm atlau- 
tic current. ..,■....,,.,,-,,., ... ;'. j, .. 

21' 



164 



HYDROIDA II 




....... boom. 



Kig. LXXXIV. The occurrence of Cnvipanulana Johtistoni in the northern Atlantic. 
In the hatched region a common occurrence is stated. 



Gen. Laomedea Lamouroux. 

Upright, synipodial colonics only occasionally exhibiting creeping parts with luil^raiiched poI\p 
stalks. The hydrothecse have a typical broad diaphragm which forms the boundary between the main 
cavity and the basal chamber. The polyps can be withdrawn entirely into the radially symmetrical 
hydrothecic. The hydranth has a club-shaped proboscis, and homogeneous gastral endoderm. 

Lamouroux (1812) gave the following diagnosis of the genus: "Polypier phyto'ide, rameux; 
cellules stipitees ou substipitees, eparses sur les tiges et les rameaux". This thus embraces the up- 
right colonies of Caiiipa)nthiriid(i\ but Lamouroux has nevertheless placed Campanularia vcrtiiillata 
in his genus Clytia. There is thus no reason to suppress the name Laomedea for later and more 
narrowly restricted genera, and we cannot, on phylogenetic grounds, break up the genus as here defined 
on account of the biological peculiarities apparent in the gonophores. Nor is a better survey obtained 
by dividing the genus according to the nature of the gonangia, which it is in most cases impossible 
to determine with certainty from the colonies obtained. And that characters should be easier to handle 
when raised to generic rank than when applied to species it is not easy to understand. 

In this genus, we find (piite exceptionally that certain species, such as Laomedea dichotoma 
(Linne) may occur with creeping growtli modification (cf. Broch 1913 p. 55); in such case, however, 
the diaphragm distinctly shows to what genus the species must belong. These creeping parts are 



HVOROIDA II 



165 



biological adaptations, which cannot in themselves afford o^ronnds for distinction of species. How they 
arise, however, has not yet been thoronghly explained. 

Laomedea flexuosa Alder. 

1850 Laoviedea flexuosa Alder, Description of three new British Zoophytes p. 440. ' 

Upright, bnsh>- colonies with nionosiphonic hydrocanlus. There is no thickening of the peri- 
derm nnder the apophyses. Branches and stem are zigzag, with a short, ringed iiydrotheca stalk from 
the apophyse at each bend. The Iiydrotheca is as a rule 172 times as long as broad, or hardly as 
mnch. In shape it is inversely conical, with sides verj- slightly cnrved and quite smooth margin 
The basal cavity is large, bonnded at the top by a distinct diaphragm. The Iiydrotheca exhibit no 
unilateral thickening of the wall. 

The gonothecse are carried on short ringed stalks proceeding from the apophyse beside the 
Iiydrotheca stalk. They are slenderly conical, as a rule tapering narrowly upward again at the distal 
part, and cut off broadl)' transversely at the distal end, without neck. The gonophores are dimorphon.s, 
the males styloid, the female heteromednsoid. 

Material : 

Iceland : Vestmano, on the beach 

Grindavik (depth not stated) 
Reykjavik ( — - — ) 
Grafarvogur ( — - — ) '^ 

Laomedea flexuosa is a boreal species characteristic of the tidal zone. On a former occasion 
(1909 p. 228 footnote) I suggested that the recording of this species from deeper water, down to 60 
metres depth near Iceland, must be due to confusion with other species. A revision of Sacmunds- 
s oil's material has entirely confirmed the correctness of this; the specimens he mentions (1902 p. 56) 
from deeper water are Laomedea geiiieulata (Linne) and Laomedea longissima (Pallas). Sjemunds- 
son later (1913 p. 78, footnote) cpiotes in support Levinsen's determinations from the cruises of the 
"Hauch" (1893); these, however, must be taken with some reserve, and they will probably only 
be found correct provided they refer to water layers of very low salinity. In fjords with an inter- 
mi.xture of fresh water and in inland seas, the limits for the tidal zone will require to I:)e somewhat 
modified, if it is to correspond with tlie conditions for fauna and flora in the tidal zone of the open sea 
shore. The deepest-living Laomedea flexuosa are met with out here on the upper Laminaria, which 
at deepest low water are not infrequently found lying dry; up in the fjords also the upj^er Laminaria 
must be taken as the limit, though they are here only found considerably deeper. Here, however, 
Laomedea flexuosa rarely goes so far down. The species is, as mentioned, boreal, ciiaracterising the 
tidal zone along the coast of Scandinavia, round the British Isles and at Iceland; it will probably, on 
further investigation, also prove to be common at the Faroe Islands. In Greenland waters, however, 
the species seems to be altogether lacking. It does not penetrate into the strictly arctic tracts. 



i66 



HYDROIDA II 



Laomedea geniculata (Liime) Lamonroux. 
1758 Sertularia getiictdata, I^inne, Systema uaturse, Ed. 10, jj. 812. 

1816 Laomedea gcniculata, Lamouroux, Histoire des Pohpiers coralligenes flexibles, p. 208. 
1864 Obclia geniculata, Allman, On the construction and limitation of Genera, p. 372. 

Upright, more rarely branched colonies with zigzag stem, the colony as a rule strongly built, 
and with an (inner) thickening of tlie perisarc under the apophyse; the stem and branches without 
rings. The hydrothecse are borne on short, ringed stalks proceeding from the apophyses. Hydrothecce 
long, about as long as broad, inversely conical with slightly curved sides. The abcauline side has as 
a rule a thicker wall than the adcauliue. The basal cavity is large, bounded at the top by a strong 
diaphragm, which, especially in colonies with strongly developed periderm, has a thickened adthecal 
part. The hydrotheca margin is even, without indication of teeth or convexities. 

The gonothecse are set on short ringed stalks proceeding from the apophyses at the side of 
the hydrotheca stalks. The gonothecse are slender, inversely conical, with a clearly defined, sharply 
tapering distal part, and short, narrow central neck. The gonophores develope into free medusae 
Obclia). 

Material : 

"Thor" 64°i6' N., 22°i7' W., depth 50 metres. 

64'-^02' N., 22°33' W., - 34 - 
Iceland: Bakkefjord, depth 25 — 32 fathoms 
Seydisfjord, — 6 — 

Vestmano, — 25 — [labelled Laomedea ffexiiosa\ 

Reykjavik, - 3—4 

Olafsvik (depth not stated) |labeUed Laomedea flexiiosa] 
Stykkisholm, depth 6 — 9 fathoms 
Bredebugt, 65°i7,5' N., 23^22' W., depth 7 — 12 fathoms 

— 65°i8' N., 23"^o2' W., — 9~io — 

Dyrafjord, on Laminaria (depth not stated) 
0nundarfjord, depth 10 fathoms 
Adelvik, - 5—5,5 - 

0fjord, on Lertura (depth not stated) 
Grimst), depth 15 fathoms 
Vidarvig, — 13,5 - 

Thistil fjord, Raudarnes 1.5 miles in S.51E., depth 18 fathoms. 
Jan Mayen, on Laminaria^ depth 15 fathoms (East Greenland Expedition). 
The Faroe Islands: Thorsliavn, depth 3—15 fathoms 
Vestiuanhavu, — 10 — 

Solmunde, on LMminaria (depth not stated) 
Svino, depth 20 fathom.s. 



HYDROIDA II 



167 



Lao)iicdca geniculata is a cosmopolite, belonging to the npper part of the littoral region ; in 
northern seas it is chiefly restricted to the Laminaria^ bnt may also occnr on deeper-growing Zostera 
and on shallow red algte in large qnantities. Albeit properly cosmopolitan, the species is nevertheless 
very rare in strictly arctic waters, but may occur here right into the White vSea. It is most frequent 
in the boreal areas. Along the coasts of Norwa)-, round the British Isles, the Faroe Islands and Ice- 
land it is present in great numbers (fig. L,XXXV). It is also mentioned from Greenland, but no de- 
finite locality has yet been recorded. 




200 m. 600 m. .- looom. 2 000 m. 

Fig. LXXXV. The distribution of Laomedca geinciihta in tlie Northern .Atlantic. 
In the hatched regions the species is abundant. 



Laomedea longissima (Pallas) Alder. 
1766 Sertularia longissima^ Pallas, Elenchus zoophytorum, p. 119. 

1858 Laomedca — , Alder, A Catalogue of the Zoophytes of Nortliumberland, p. 121. 

1868 Obelia — , Hincks, A History of the British Hydroid Zoophytes, p. 154, pi. 27. 

1868 — flabrllata, Hincks, I.e. p. 157, pi. 29. 

Large graceful colonies with monosiphonic, brown stem, generally flexuous. I'rom this pro- 
ceed secondarily ramified branches, which again give off a hydrotheca stalk from the apophyse at 
each bend. There is no thickening of the periderm under tlie apophyses. The hydrothecai are about 
twice as long as broad, slender, inversely conical, with more strongly curved basal part. The hydro- 
theca margin is more or less curved, at times with distinct teeth, at others quite smooth. The basal 
chamber is fairly large, and bounded at the top by a finely built l)ut distinct diaphragm. 



i68 



HYDROIDA II 



The gonothecae are borne on short, ringed stalks, proceeding from the apophyses beside the hydro- 
theca stalks. They are oblong, inversely conical, distally cnt off transversely with a central short 
and narrow, almost tnbnlous neck. The gonophores develope into free nieduste {Obelia). 

Material: 

"Tlior" 64°02' N., 22°33' W., depth 34 metres | labelled Lnonifdca gclafiiiosa\ 

— 63°3o' N., 20°i4' W., - 80 — 

— 58°! I ' N., 2°28' W., — 60 - 
Greenland: Jakobshavn (depth not stated) 

Provens havn ( — - — ) 

Holstensborg ( — - — ) 

Tasinsak, depth 3 — 5 fathoms (East Greenland Expedition). 
Iceland: Bernfjord, depth 6 fathoms | labelled Laoiiicdea flcxiiosd\ 
Hornafjord (depth not stated) (labelled Laomedca Lovenii] 

Vestmano, depth 25 — 28 fathoms [some of the specimens labelled Laomedca flcxiiosa] 
10 miles W. of Akranes, depth 26 fathoms [labelled Laomedea flexiiosa\. 
vStykkisholm, depth 20—30 fathoms [labelled Laomedea flex7tosa\ 
Kollafjord, — 4 — 5 — 

Dyrafjord (depth not stated). 
The Faroe Islands: 5 miles N. by E. of Myggena;s point, depth 50 fathoms. 




"" '" 600m looom, _ zooQirx. 

Kig. I.XXXVl. The distribution of /.aomrdca lotigissima in the Northern .'Vthintic. 
In llu- liatched regions a connnon occurrence is stated. 



HYDROIDA II 



169 



Sterile colonies of this species with almost or entirely smootli margin may at times present a 
certain resemblance to Laomcdea tlrxuosa, and have frequently been confnsed with this species by 
Sa.Mnnndsson. — Nntting- (1915 p. 73) endeavonrs to revive Obclia flabcllata Hincks on the gronnd 
that the extreme branches of this species exhibit dichotomons ramification, whereas in the present 
species they are "flabellate"; nnfortnnately, however, he does not further explain the difference between 
the two terms. In the present colonies, both might often apparently be applied to the same branch. 
Nor does his other distinctive character, the fact that the branches in Obclia longissima are "regularlv 
alternate" while those in Obclia flabcllata are "alternate or opposite" give ns any sound basis to work 
on. Bonnevie (1899 p. 71) is undoubtedly right in uniting the two .sjjecies, and they cannot be 
revi\'ed on the strength of what Nutting here seeks to show. 

Laojiicdca lo)igissinia appears to be a cosmopolitan species, albeit the data on record from 
tropic-subtropical waters are but scanty. The species belongs to the upper third of the littoral region, 
and goes far up into arctic waters, where it has a circumpolar distribution. In the area investigated 
(fig. LXXXVI) it appears to be entireh- lacking in East Greenland waters, but is otherwise fairly re- 
gularly met with on all coasts. 

Laomedea hyalina (Hincks) Levinsen. 
1866 Gonothyrcra Ityalitia, Hincks, On new British Hydroida, p. 297. 
1893 Laomedea — Levinsen, Meduser, Ctenophorer og Hydroider, p. 28. 

Finely built upright colonics with monosiphonic main stem, the latter being, like the main 
branches, generally brown in colour. The colony often assumes a bushy appearance, owing to irre- 
gular ramification. The hydrotheca; are carried on short ringed stalks proceeding from the branch 
apophyses; the latter are set in a plane on the branch directed alternately to either side. The hydro- 
thecse are slender, iuN'ersel}' conical to cylindrical, tapering somewhat more at the basal part toward 
where the stalk begins; the^" are twice to tliree times as long as broad. The hydrotheca margin is 
furnished with low teeth, having a slight, often almost imperceptible median sinus in their distal 
end, which is cut off almost straight, so that they are divided into two denticles; from this sinus a 
slight furrow runs for a varving distance down the hvdrotheca on its outer side. The basal chamber 
is small, bounded at the toj) by a thin, but well developed diaphragm. 

The gonothecfe are borne on short, ringed stalks, proceeding from the apophyses beside the 
hydrotheca stalks. They are inversely conical, cut off straight at th.e distal end, without neck. The 
gonophores develope into cr^-pto-medusoid mecouidia, which extend out from the gonotiieca without 
breaking away; the larval development takes place in the interior of the meconidium. {GofiothyrtPa 
medusae). 

Material: 

"Ingolf" St. 34, 65°i7' N., 54"i7' W., depth 55 fathoms. 

"Thor" 66°23' N., i4°24' W., — 45 metres 

— 65°52' N., 23°58' W., — 62 — | labelled Laomedea Loveni] 

— 64=16' N., 22°i7' W., - 50 

The Ingolf-Expedilion. V. 7. 



I JO 



HYDROIDA II 



"Thor" 64''o2' N., 22°33' W., depth 34 metres 

— 63°30' N., 20 14' W., — 80 — I labelled Laoniedea Loveui'\ 
Greenland: Proven (depth not stated) 

Umanak ( — - — ) 

Christianshaab ( — - — ) (labelled Go)iothyrcca Love7ii\ 

Egedesminde ( — - — ) \\dA:)t\\&& Gonothyrcea Loveni q\\^ Obelialo)igissima\ 
Store Hellefiskebanke, depth 32 fathoms 
Sukkertoppen, on Psolus and Boltcnia (depth not stated) 

— (depth not stated) [labelled Obelia longissiiii(i\. 

Iceland: Hvalfjord, depth 22 fathoms. 

The Faroe Islands: withont further details |labelled "Gonothyrcea Loveni] 
6 miles N. by W. of Store Kalso, depth 60 fathoms 
Deep hole at north point of Nolso, — 100 — 

Laouicdca hyalina is very closely allied to the Lao)iicdea J.oveni Allman, so mnch so that the 
two species have very often been confused. The characteristic distinctive marks of LaoDiedea Jiyalina 
are the fine narrow furrows running from the teeth some way down over the side of the hydrotheca, 
often giving the teeth themselves a double point. Nutting (1901 p. 352) mentioned intermediate 
forms between the two species fronr Plymouth; as however, the furrows in question are not noted by 
Nntting in the American waters, it is doubtful which of the species he has here been investigating. 
Probably all his specimens were typical Laoniedea Loveni. 

jMonicdea Iiyaliiia must, from the data on record, be characterised as an arctic boreal, atlantic 
species. Its true home ajipears to lie at the transition between boreal and truly arctic regions, and 
from there it extends both north and south, evervwhere within the upper third of the littoral region. 
Kramp (1914 p. 1071) notes the species as circumpolar, citing in evidence Clark (1876 p. 215) who 
mentions a Gonothyrcea hyalina from Alaska. Mark tanner-Tn rneretscher however, (1895 p. 408) 
has pointed out that Clark's specimens represent the type of a distinct species, Laoniedea Clarki 
(Marktanner-Turneretscher). The validity of the species may seem somewhat doubtful, and it is highly 
probable that Kramp is correct in his geographical characterisation, but new and conscientious in- 
vestigations in American waters will be needed before we can be fully certain. Laoniedea hyalina is 
widely distributed within the waters investigated (fig. LXXXVII). It is surprising to find that a 
species having so wide a distribution in the arctic regions appears to be altogether lacking i East 
Greenland waters; it is otherwise of general occurrence within tlie area concerned, but becomes less 
frequent around the British Isles and off the southern west coast of Norway. 

Laomedea gracilis M. Sars. 
1851 Laomedea gracilis, M. ,Sars, Beretning om en i Sommeren 1849 foretagen zoologisk Rejse, p. 138. 
1868 Gonothyrcea gracilis.^ Hincks, A History of the British Hydroid Zoophytes, p. 183, pi. 36, fig. i. 

Upright colonies, slightly and irregularly branched, finely and stiffly built. There are no 
distinctly prominent apophj'ses, but the branches and hydrotheca stalks proceed from a faintly marked 



HYDROIDA II 



171 




200 m, _, 600 m ._.____IOOOrTJ. _ . ^. ^ ^ 2 coo m 

Fig. LXXXVII. The distribution of Laoiiiedfn Jiyalnia in the Northern Atlantic. 
In the hatched re"ion the hterature notes a scattered occurrence. 




Fig. LXXXVIII. The di.striliution of Laomedca grncilis in the Northerti Atlantic. 
In the hatched regions the literature notes a scattered occurrence. 



1-2 HVDROIDA II 



monosiiDhoiiic main stem, which not infrequently appears to be dichotomously branched. The bran- 
ches and the hydrotlieca stalks are ringed close above .their origin, and below the hydrothecse, other- 
wise smooth. The hj'drothecrc are twice to three times as long as broad, cylindrical, or rather inversely 
conical, passing over by an evenly curved transition into a short, almost cj'lindrical basal part; the 
basal chamber is small, bounded at the top by a fine, well developed diaphragm, often somewhat 
ass\'metricallv placed. The hydrotheca margin is provided with seven to fourteen markedly prominent 
pointed or pointedly rounded teeth. 

The gonothecce are attached by short, ringed stalks proceeding from stem or branches, rarely 
from the stolons. They are inversel)' conical or slightly oval, elongated, cut off transversely at the 
distal end, without neck. The gonophores develope into cr\-ptomedusoid meconidia, projecting from 
the gonotheca without breaking away. The larval develcrpment takes place within the interior of 
the meconidium {Gonof/iyrcni medusse). 

Material : 

"Thor" 64°02' N., 22°33' W., depth 34 metres 

Iceland: (without further details) on the back of a Dinciiiatttra fcrox taken from a Soiii/iiosus 
iiiicrocephaliis. 

Laoincdea gracilis is a southern visitor to the northern waters (fig. LXXXVIII) where it pene- 
trates up to tlie northern jjoint of Norway. The species is altogether of rare occurrence here, l)ut 
has been taken more especially about the British Isles. One or two finds show that it also occurs 
sparsely at tlie Faroe Islands and .south-west Iceland, always in the middle or upper third of the 
littoral resrion. 



Gen. Bonneviella (Broch). 

Stolonial colonies with enormous, often slightly bilateral liydrothecce, having a finely built 
diai)liragni. The large polyps can be withdrawn entirely into the hydrotheca. The hydrantli has a 
crown of strong tentacles witli multiserial endoderm; the oral part is thin, forming a thin kmiella, 
consisting of two cell-layers, which a little above the tentacle base extend out like a velum in towards 
tlie central oral aperture. Tile tentacle base thrusts itself into the polyp, .so that a large proboscoidal 
cavity is formed between tliis and the oral aperture. The gastral endoderm is uniformly developed. 

As already mentioned, I am unable to agree with Nutting, who is inclined (1915 p. 94) to 
snpport the view advanced l)y mc in a former work (1909 p. 197), that the ectoderm covers the ten- 
tacle base and t!ie inner side of the velum-like proboscoidal ]iart. Kuhn (1913 p. 253) is justified in 
doubting whether the part in question can be reckoned as belonging to the endoderm, and I am 
more disposed to follow him here, considering the part as an extreme development of the indifferent 
endoderm cell-layer, as found for instance on the proboscis of Caiiipanu/ariidtr. The point can, how- 
ever, only be decided by study of the polyp development. The systematic position of the genus is 
still altogether doubtful. 



HYDKOIDA 11 



173 



Bonneviella grandis (Allmaii) liiocli. 
1876 Caiiipa)iiilaria grandis. Allniaii, Diagnoses of new Genera and Species, p. 259, pi. 12, figs. 2 — 3. 
1899 La/oca gigaiitca^ Bonnevie, Den norske Nordhavs-Expedition, p. 68, pi. 6, fig. 2. 
1909 Bo)i)icviella grandis, I5rocli, Plydroidennntersncluingen, II, ]). 198. 

The colonies form enormous ujiriglit and irregnlarh- branched rhizocanlonies. From the tnbes 
proceed In-drotheca stalks of differing length, often segmented, with a spherical swelling innnediately 
below the hydrotheca. The latter are twice to three times as long as broad, swollen for the lower 
third part, somewhat narrower above, with expanded margin; in trans\^erse section, the ludrotheca 
is circular below, oval nearer the aperture; the aperture itself is as a rule somewhat asymmetrical, 
the margin quite smooth. The basal cax'ity is small, bounded at the top by a quite thin diaphragm. 

The gonothecte proceed from the tubes of the stem; they are more or less closely set, and 
occur scattered about all over the colony. The gonothecce are egg-shaped to spindle-shaped with six 
to eight longitudinal ribs and a short, narrow trumpet-shaped neck. 

Material: 

Iceland: 64''i7,5' N., i4°44' W., depth 75 meters 5°i2 
The Faroe Islands: Thorshavn (depth not stated). 

The genus Boiuicviclla includes several species from the northern Pacific, for the further de- 
scription of which we are indebted to Nutting (1915 p. 95). One of these species is Bonneviella 




200 rn. boom ^ .- ^ looo m. — 2000 m 

Fig. LXXXIX. Localities of Bonneviella grandis iu the Northern .\tlantic. 



174 



HYDROIDA II 



grandis^ first described from some colonies from Japan, Tsngor Strait, preserved at Copenhagen. The 
species differs from the others by its longitudinally ribbed gouothecas; the other species in which the 
gonangia are known, have the gonothecse transversely furrowed. The next find of Bonneviclla grandis 
was made off the west coast of Norway. We have since learned, that the species, besides occurring 
at several places in the North Pacific, is also widely distributed in European waters. It has been 
met with in the Barents Sea, at Lofoten (fig. LXXXIX), at ]\Ioldoen near Stat on the west coast of 
Norway. It is mentioned from the south-east point of Iceland and from Fyllas Banke in Davis Strait. 
We may now add some new localities; the Faroe Islands, and outside Isafjord, Iceland, where it was 
taken by the "Michael Sars" in the summer of 1903. Bonnri'it'lla graiidis nmst thus be characterised 
as a boreal circumterrestrial species, belonging to the lower parts of the littoral region and the upper 
portion of the abyssal. 



III. Addenda to the Athecate Hydroida. 



In going through the athecate hjdroids, some few glasses were overlooked, and are here 

included. 

Corymorpha nutans M. Sars (Part I, p. 31). 

Iceland : Keflavik (depth not stated) 

Bredebugt 65°! 2,5' N., 23^28' W., depth 36 fathoms. 

Corymorpha groenlandica (Allman) Broch (Part I, p. 33). 
"Ingolf" St. 15 66''i8' N., 25°59' W., depth 330 fathoms -^ 0,75° 

This find forms an interesting complement to the former data (cf. Part I, text fig. I); it lies in 
Daumark Strait, on the northern slope of the threshold, and shows that the species also occurs be- 
tween Iceland aiul Greenland. 



Family Branchiocerianthidae. 

.'\thccate hydroids without calcareous .skeleton. The tentacles of the grown polyp, which are 
all filiform, make two main circles; the tentacles have a central cavity not connected with the gastral 
chamber. The supporting lamella exhibits no particular development in any of the tentacles. The 
h\(haulhs arc bilateral in structure. At the base of the proximal tentacles, numerous radial canals 
occur, reducing the niesogloeal formations to a minimum. The gastral chamber is divided by a hori- 
zontal sciUuni into two part.s, a smaller proboscoidal, and a larger basal. The gastral endoderm is 
homogeneous in both. 

Gen. Branchiocerianthus Mark. 

The polyps are bilaterally .s\inmetrical, the stalk being excentrically attached; the oral aperture 
also is excentrically situated, being thrust over towards the opposite side of the point where the stalk 



HVDROIDA II j_- 



is attached. Tlic hydraiith lias a proximal tentack- crown, the growth of which takes place from the 
part of the hydranth periphery nearest the stalk, wliere the shortest tentacles are found. The tentacles 
of the oral circle are homogeneously developed. The periderm of the stalk is reduced and soft. The 
blastostyles are situate between the tentacle crown.s, the youngest ventrallv above the point of at- 
tachment of the stalk. The pohps are solitary. 

Allman (1888 p. 5) described the first Bnvnchioieriaiitliiis species, which was brought home 
by the "Challenger", under the name of Mcnwcaiilus imprrator. The family Moitocaulidce had been 
previously founded by A 11 man n (1871 p. 395) with the following diagnosis: "Hydrocaulus .solitary, naked. 
Hxdranths with a jjroxinial and a distal set of filifonu tentacles. — Gonophores in the form of fixed 
sporosacs". This diagnosis thus makes no mention of the essential point, to wit, the bilateral character 
of the polyp. Nor is any reference to this found under the heading of the only genus, Monocau- 
lus, which is thus described: 

"Hvdranth abruptly distinct from the hydrocaulus; proximal tentacles longer than tlie distal 
and disposed in a single verticil near the base of the hydranth, the distal set scattered o\er a zone 
close to the summit of the Indrauth. — vSporosacs borne upon peduncles, which spring from the body 
of the hydranth between the proximal and distal sets of tentacles. 

The genus AfoHocattlns is constituted for the Corxmorpha glacialis of Sars, a form which, 
though its trophosome is that of a Cory/i/oip/ia^ is yet strongly distinguished from the true Corymor- 
phas by its adelocodonic gonophores" (Allman 1871, p. 396). 

In addition to Coryniorpha glacialis, Allman also places Corynwrpha prnditla L. Agassi/, in 
the genus, this being a species with free medus;e. I^ater on, Corymorpha groenlaiidica is also placed 
in the same genu.s. And here, finally, Monocaiilus iinpcrator is likewise included, Allman (1888 p. 5) 
having entirely overlooked the bilateral .structure of the species, and disregarding the morphological 
peculiarities noted in his descriptions. 

With reference to Corymorplia I have pointed out that A 11 man's typical Mofiocauhis, Cory- 
morpha glacialis M. Sars must remain in the genus where M. Sars placed it, like Monocaulus grorn- 
huidica Allman, the only species which entirely answers to the diagnosis given by Allman. It would 
therefore be altogether wrong to follow the suggestion given in "Nomina conservanda" (cf. p. 53) and 
retain the generic name Moiiocnuhis for a genus where Mo>tocaiilt(s imprrntor has been somewhat 
arbitrarily chosen as type, the more so since the essential feature of the species, which is even cha- 
racteristic of the genus as a family type, was distinctly empha.sised by E. L. Mark in 1899 in his 
description of the central American Pacific species Braiicl/iocrriai/lkus nrccoliis Mark. Since then, the 
genus has been referred to in all leading works under the generic name given it by Mark, Braii- 
chiocerianthiis, and as the species in question have been accorded only the briefest mention in the 
handbooks, there will be no confusion caused by general adoption of the appellation. Moreover, after 
the publication of the fundamental studies on Brarichioccriaiithns by Mark (1899), Miyajima (1900), 
and Stechow (1908, 1909) it would certainly be confusing to adopt the name Monocaulus. 

The genus Braucliioceriaullnts was hitherto only known from the Pacific (Alaska, Japan, Pa- 
nama) and the Indian Ocean (Beluchistan, Oman, and East Africa). Stechow, in his description of 



176 



HYDROIDA II 



Branchiocerianthus impcrafor (1909, p. 71) states: "Da im iihrigen die Familie' ganz kosniopolitiscli ist 
so durfen wir wohl annehmen, dass Branchiocerianthus-Arten auch ira Atlantischen Ozean vorkomnieii, 
bisher aber nur wegen ihres lyebens in grosserer Tiefe nocli nicht gefunden worden sind". 

Excellent proof as to the correctness of this supposition has now been furnished by the finding 
of a Branchioceriantliiis in the deep part of Davis Strait, where it occurs together with other repre- 
sentatives of a southerly deep-sea fauna. Stechow's characterisation of the habitat of the genus as 
"Kaltwassergebiet" however, is biogeographicalh- erroneous; Bniuchioccriaiitliiis has not yet been met 
with in the cold area, and is hardly likely to prove a characteristic element in the fauna of that region. 
The genus belongs to the abyssal region of the warmer seas, or strictly speaking, that portion of the 
same which makes the home of the "intermediate fauna". The temperature here may certainly fall 
pretty low in certain places, but is never below 0°. The "Kaltwassergebiet" would include the cold 
area, where tlie temperature is constanth' below 0°. 

Branchiocerianthus reniformis n. sp. 

(PL I, figs. 2-5). 

The liN-dranth, viewed from below, has a distinctly kidney-shaped appearance, with a deep 
(ventral) sinus reaching right in to the stalk. Owing to the depth of this incision, the stalk appears 
comparatively centrally situated, the distance to the dorsal edge (6 mm) being slighth' more than 
that between the stalk and the margin of the disc perpendicular to the dorso-veutral axis (4,5 mm). 
The oral aperture seems to be somewhat more excentrically placed, benig distant between a fourth 
and a third of the diameter of the disc from the dorsal margin of the disc. The oral aperture is 
very large, and in the present specimen it is curved over, revealing the highh' folded gastral endo- 
derm (PL I, fig. 3). It would almost seem as if the margin of the oral aperture were divided into 
lobes; from the single siDccimen here available, however, it is impossible to decide with certainty, 
whether this is natural, or due to accidental damage. The margin of the oral aperture is curled, with 
a closely packed tentacle crown, showing indications of multiserial arrangement. The oral tentacles 
are everywhere round in transverse section, and are strongly built. The basal tentacles form a single 
circle; they are very long, with exception of the ventral ones, which are placed along the margin of 
the disc in the incision. In the incision itself, the tentacles decrease rapidly in length in towards 
the stalk, at its base are the youngest tentacles, which are quite small. The basal tentacles are later- 
ally coni])ressed at the l)ase, where they easii)' fall off; in tlie present specimen, only the tentacles in 
tlie incision and a pair beside it are intact, the remaining ones having fallen away. The stalk of the 
polyp is thin, longitudinally strij)ed. The short basal part is covered witli numerous fine root hairs 
extremely closely set, forming a tangled mass round the end of the stalk and entirely covering it 
there. There is no zone of incipient root hair formation discernible above the developed part. 

The blastostyles form a crown, interrupted ventrally, about the hydranth between the tentacle 
crown.s, nearer the ba.sal. The blastostyles are closely set in a crown which may be up to triple- 
rowed. The large blastostyles divide near the base at once into two or three main brandies of equal 
size, which later (PL I, fig. 5) again divide dichotomou.sly at intervals two or three times. The top of 

■ 1. e. Corymorpha and /Iranrln'ocrrimiUnis. 



HYDROIDA II J 



the blastostyle is shaped rather like a chister of grapes, the outermost swellings, shown in the figure, 
consist each of a compact accumulation of incipient gonophores. Nematocyst-bearing terminal buds 
appear to be altogether lacking. The size of the blastostyles decreases nearest the ventral interval, 
whence a new formation evidently takes place. 

With regard to the anatomical character of the polyp, we must notice the large mesentery 
which divides the gastral cavity into an upper (oral) and a lower (basal) section; it has a large median 
opening. The radial canals have a large lumen; they do not appear to divide, and alternate with the 
tentacles, and thus do not stand in open connection with the latter; their number corresponds to that 
of the proximal tentacles. — The blastostyles are hollow, and communicate openly with the interior 
of the polyp, but it was impossible to determine exactly whether their communication with the gastral 
cavity is direct, or proceeding indirecth- through the radial channel. 

Material : 

"Ingolf St. 28 65°i4' N., 55^42' W., depth 420 fathoms, 3,2°. 

The only specimen procured presents the following features: Total length 120 mm., of which iiomm. 
fall to the hydrocanlixs. Distal diameter of the stalk 3 mm., close above the root hairs the transverse section 
is 7 mm. The polyp disc has a total breadth of 12 mm. and a length of 9 mm., measured from the 
bottom of the ventral incision. There are 85 proximal tentacles; the longest of those intact is 55 mm. 
The distal tentacles are very closeh- set, often displaced, giving a slight indication of three rows; 
there are between 80 and go oral tentacles of np to 5 nun. length. The blastostyles are closely packed 
together, and form three indistinct rows, the longest is 4 mm.; there are between 70 and 80 in all. 

On comparing the present specimen with the species of Brattchioceriatifhus previously described, 
we find several points of difference, albeit none very striking in itself. The peculiar kidney-shaped 
appearance of the disc (PL I, figs. 2 and 3), as also the curled margin of the oral aperture, wonld 
seem to be different from the species previously described, and has led me to regard the specimen for 
the present as representing a distinct species, BrancJiioccriantJins rcnifonnis. The lack of terminal 
buds bearing nematoc\sts in the blastostyles brings the species near to Braiichioceriantlnis n. sp. Stecho w, 
(1913 p. 54) from which, however, it is immediately distinguished by its undivided radial canals. The 
habitus of the hydranth distinguishes it from Braucliioceriaiitlms iirccolns Mark; this may, however, 
possibly be taken as due to a difference in the state of contraction. From Branchiocerianthus impe- 
rator (AUman) again, the species differs in the lack of nettle buds on the blastostyles. From the appe- 
arance of the specimen in 1904, Braiichioceruuif/iiis rcniformis has also a different colour; the body of 
the polyp was then white, the blastostyles being a deep violet blue; now, after having lain many 
years in alcohol, it is an even grey. 

The individual can hardly be fully grown, and corresponds in point of size only with the 
smaller specimens of Branchioceriavthus urceolus found. The number of proximal tentacles agrees 
mainly with that in this species, but there are far fewer distal tentacles; save for one of Allman's 
specimens of Brancliioceriaiithus impcrator (1888) all the other individuals found belonging to this 
genus had considerably more distal tentacles. The number of blastostyles takes up an intermediate 
place between the two mentioned species, and is somewhat lower than in Branchiocerianthus n. sp. 

The Ingolf-Expedition. V. 7. ^ 



j_g HYDROIDA II 



Stechow (1913). As, however, the specimen is unique, and moreover, apparently not fully grown, 
these points should not be considered as of too great importance in the present state of our know- 
ledge. For the present, it will be most correct to regard the specimen as representative of a distinct 
species, bearing in mind, however, that subsequent investigations may possibly show it to be identical 
with one of those formerly described. 

Branchioceria)ithus reniformis will probably, as the find suggests, prove to belong to the abyssal 
reo-ion. Its occurrence shows that the genus is of circumterrestrial distribution. 



IV. Zoogeographical observations on the Hydroid Fauna 

of the North Atlantic. 



The study of the bathymetrical distribution among hydroids still leaves much to be desired; 
the data on record are still somewhat scanty, and merely suffice to give an occasional glimpse of the 
regularity which will doubtless be found to prevail throughout this animal group, just as in others. 
It has been a generally accepted notion, and is so to some extent even now, that a marine animal 
species with a wide horizontal distribution will prove of shallower occurrence the farther north it is 
found in our waters, or rather, the farther it penetrates into the cold areas. This rule, however, is not 
universally applicable. True, we find that species which must be regarded as more or less arctic are 
met with in more southerly tracts in the deeper water-layers, but on the other hand, warm atlantic 
character forms which are found farther south up in the littoral region often exhibit, in the few 
northern finds made, a tendency to prefer even much greater depths. Evidently then, the biophysical 
conditions here approach more nearly to those prevailing in the southern home of the species, though 
we cannot at present find any further explanation of this. At any rate, the question is seen to be a 
good deal more complicated than was at first supposed, and tlie available data are unfortunately far 
from sufficing to give a thorough exposition of the biogeography in hydroids in the northern waters. 

In this connection, it will not be out of place to explain one or two expressions which are 
constantly recurring when dealing with the different species. I refer to the terms littoral and abyssal 
region. I have followed the general international accej^tance in using "littoral region" for the uj^jDer 
3—400 metres of the sea floor, "abyssal region" for depths beyond. It is true that certain northern 
writers have sought to give the terms in question new and sometimes quite different meanings. 
This, however, gives rise to confusion, and further complicates the still somewhat new field of research 
known as biogeography. The terms used should be as nearly as possible invariable, and should not 
require to be defined anew by each writer, as has hitherto been the case. Indeed, it might almost 
seem well to discard altogether the term littoral region, since it appears to be interpreted in almost 
as many different senses as there are writers in Scandinavia. I have here, however, as indicated, 
employed the expression in the general sense in which it is used outside the works of the scientists 
referred to. 



HYDROIDA II j-Q 



A great majority of the northern hydroids are decidedly inhabitants of the Httoral region, and 
among these we find a number of species which characterise its upper part, the tidal zone. This zone 
comprises, on open sea coasts, the belt between high- and low-water marks; in fjord grounds, how- 
ever, where the water is mixed with fresh, we are obliged, on account of the altered hydrographical 
conditions, to draw the lower limit somewhat farther down, where the laminarijc begin. The tidal 
zone is in all parts of the northern waters characterised by Fucoids, and is distinguished in hydrographical 
respects b>- its rapidly and widely fluctuating temperature and salinity. Certain writers have objected 
to the validity of this zone as such, on the ground that all its character organisms are also normallv 
to be met with deeper down; this, however, mereh^ reveals a lack of knowledge as to the true state 
of the case. We may in ihe first instance take a species which has been utilised in several works 
for giving the zone in question its other name; to wit, Bala mis balaiioidrs Linuc. This species does 
not normally penetrate deeper down. In this connection, however, we are naturall\- more interested 
in the characteristic hydroids; which are: Coryiic piisilla, C/a7'a Diitlticornis and Laovtedea flextiosa. 
These species are altogether restricted to the tidal zone, and their occurrence in deeper water in the 
open sea must be regarded as an anomaly, unless due to erroneous identification on the i:)art of the 
investigator. It is likely that also other species, especially certain Coryiir, should be grouped among 
the character forms of the tidal zone, but we have not yet sufficient data to assert this as a fact. The 
mentioned species are so completely restricted to the area in question, — which is not rich in species 
on the whole — that we are fully justified in distinguishing the tidal zone as a separate area with a 
fauna of its own. 

The deeper zones are, from the character of the investigations, somewhat less strictly defined. 
It would nevertheless seem that species such as Endcndriuvi IVr/g/ifi, Sertularella rugosa^ and Tmo- 
viedea geniculata are altogether restricted to the Laminaria zone, while Dynameiia pnitiila is common 
to the shallower part of this zone and the tidal zone. The great bulk of the hydroids commence to 
appear in the lower parts of the laminaria zone, reaching their most luxuriant occurrence in the red 
alga zone and the lower parts of the littoral region. 

On passing down be\-ond about 600 metres depth, however, the lower limit of what may be 
called the "coast bank region", we encounter a sudden and ver\- marked decrease in the number of 
hydroids; below this limit, their occurrence must be called more sporadic, and there are only a few 
unique species which have their chief occurrence at greater depths. The deep-sea species in question, 
which have their habitat down here, exhibit also, in each case, a merely sporadic occurrence, — though 
we cannot, of course, entirely disregard the possibility that this apparent state of things may in re- 
ality be due to lack of sufficiently exhaustive investigations in the proper localities. A clear indica- 
tion of the inadequacy of our knowledge as to these deeper parts of the sea floor, even in the North 
Atlantic, is afforded by the "Ingolf" expedition's unexpected finding of species such as Branchiocerian- 
tlitis rcniforiiiis, Zygopliylax bianiiata, Graminaria confcrta, Polyplumaria profunda, and Sertularella 
amphorifera close south of the submarine ridges in Davis Strait, Danmark Strait, and between Ice- 
land and the Faroe Islands. 

With the paucity of available material, it is of- but little interest to go into details regarding 
the bathymetrical distribution of the species. On the other hand, it is well worth while to consider 



23' 



i8o 



HYDROIDA II 



the extent of certain horizontal areas of distribution, and we may first of all endeavour to obtain a 
clearer idea as to what is commonly known as the boreal region, the definition of which at times 
appears to be somewhat vague. In the case of the hydroids, the data on record furnish valtuible 
hints, as will be seen from the following. 

Theoretically speaking, the northern limit of the boreal region should be drawn as the bound- 
ary where southern species of general occurrence in northern waters cease their northward progress, 
while similarly, the southern limit should mark the extreme margin of the arctic-boreal species' distri- 
bution. It should, moreover, constantly be borne in mind that the boreal area is decidedly a "mixed" 




•■ 2 00 n). boom. _._.looo/n. 2 ooo m. 

Fig. XC. The occurrence of Netncrtesia antennina, Dynamena piimila, and Thiijaria thuja, three species which 

are common in more southern European waters, but which only have been found in high arctic waters quite 

exceptional!)-. (The red line approximately indicates the limit of the cold area). 

area; strictly boreal species are extremely few in number, among hydroids as among other animal 
groups, and will in many places penetrate out beyond the limits of the narrower region. — x^s ex- 
amples of southern species extending up to the frontier of the arctic areas we may take for instance 
Netncrtesia antennina, Dynavicna piinii/a, and Thiijaria tintja. These three are practically never found 
in true arctic waters; where finds have been made, it was always at places where north-going cur- 
rents render the limits uncertain, or where the varying conditions of the coastal water afford southern 
species a precarious refuge in some isolated spot within the arctic seas. At such places we may en- 
counter, for instance, scattered colonies of Dynatiieiia puviila. As a general rule, we find (fig. XC) 
that these species do not cross beyond the limit of the cold area as indicated by the course of the o° 
isotherm. At the same time it should be noted that the mentioned species are by no means infre- 



HYDROIDA II 



i8i 



quently met witli in Davis vStrait, which is thus proved to belong, at any rate in part, to the boundary 
waters of the boreal region. Yet the species penetrate only quite exceptionally into the west Green- 
land fjord area, which must be regarded as purely arctic, partly on account of the intermixture of 
melting water from the glaciers, and partly owing to the north-going branch of the East Greenland 
Polar Current, which turns round Cape Farewell and runs some distance up the coast Here we still 
find Dyiiaiiitna pnmila sporadicall\', probably because the investigations were carried out at a time 
when the summer heat had brought the surface temperature up a little, enabling the species just to 
exist for a brief while, and under difficulties. Not until we reach the waters between Holstensborg 




20Q rn. boom. looom, 2000m. 

Fig. XCI. The occurrence of Halecium miiricatum, and Sertiihirella tricuspidata, two arctic species which 
penetrate into the southern parts of the boreal region. (The red hue approximately indicates the hnut 

of the cold area). 

and Egedesminde do the boreal elements in the coast fauna become more pronounced. In Danmark 
Strait, between Greenland and Iceland, we see that the finds group themselves closer as soon as we 
pass south of the o° isotherm, where the depth conditions are more favourable. Despite their positive 
bottom temperature, the shallower North-Icelandic waters seem to take a more arctic character, though 
this may, as we shall presently see, perhaps be equally well explained as due to insufficient investi- 
gation. Between Iceland and the Faroe Islands, the species move up to the verge of the cold area, 
but do not pass it. And the whole of that part of the Norwegian coastal banks which falls witliin 
the Hmits of the chart presents an entirely boreal character. - 

Turning now to the other side, and taking the distribution of the arctic-boreal species Hale- 
cium >intricatuin and ScrtularcUa tricitspidata, several peculiarities are also here apparent (fig. XCI) 



I82 



HYDROIDA II 



Both species occur in Davis Strait, very commonly on both sides of the o° isotherm, but do not go 
deeper down from the coastal banks. Both, however, are apparently entirely lacking along the east 
coast of Greenland south of 76° N. This may be due to paucity of investigations, but it would seem 
likely that the reason is rather to be sought in the fact that the water, owing to extensive interming- 
lino- of fresh and ice-cold glacier water is poor in suitable forms of nourishment, and unfavourable to 
the growth of hydroids generally. Altogether, onl\- a very few hydroids have been found along the 
range in question, the finds in question invariably consisting of but few and small colonies. The 
apparent absence of the meutioued species in North Iceland waters, on the other hand, would seem 




200 m. 600m. .^ looom. 2000m. 

Fig. XCII. Localities of the arctic deep sea species Myriothela phrygia D, and Corymorpha groenlandica o, 
and of the southern, exotic guests Grammaria conferta * , Zygophylax biarmata T, Polypbimaria profunda •, 
Cladocarpus Diana ■, Si'rtulanl/a amphorifera A, and Sertiilaria (?) ttibiiUformis ff- (The red Hne approxim- 
ately indicates the limit of the cold area). 

rather to be due to lack of sufficient investigation; it is difficult to find any other explanation. The 
frequent occurrence of the species round all the remainder of Iceland's coast shows that tlie range in 
question must as a whole be included in the boreal area; there is no indication of warmer tendency 
at any place on the true coastal banks here. The ridge between Iceland and the Faroe Islands, and 
the waters round the latter down to 600 metres' depth must be taken as belonging to the boreal 
region, as also the western Scottish waters. The North Sea also is boreal, and the Norwegian coast 
to the extent shown on the chart. 

Before concluding this characterisation of the boreal area, two other geographical groups of 
less frequently occurring hydroids should be considered. These are the deeper-living inhabitants of 
the cold area, represented b)' Myriothela phrygia and Corymorpha groenlandica^ and the exotic warm- 



HYDROIDA 11 



183 



water species of the Atlantic, found here and there in the waters investigated (fig. XCII). Myriothela 
phrygia is apparently an easterly arctic species which penetrates ont to the southern limit of the 
cold area; it has in a single instance been taken on the southern, deep slope of the Wyville-Thomson 
Ridge, brought thither probably by larval transportation. Corymorfiha grocnlandica moves out every- 
where to the boundary, and has once passed beyond it, in Davis Strait, on the Store Hellefiskebanke, 
and between Iceland and the Faroe Islands, probably likewise as a result of larval transportation. 
Both species are, moreover, met with in a single isolated spot far up in the boreal region, to wit, in 
Trondhjem Fjord, where they must probably be regarded as relicts — The opposite group, the exo- 
tics, will be represented by Graiiimaria confcrta, Zygophylax biarmata^ Polypluviaria pro/ujida, and 
Serticlarella amphorifera. One or two of them may in southern localities exhibit a shallower occur- 
rence; here in the north, however, save for a single find of Polyplumaria profunda up in Danraark 
Strait, they are not met with beyond the 600 metre curve, nor within the true boreal region. 

A study of the hydroids leads then to the result, as seen from the instances given, that the 
limits of the boreal zone as against northerly or arctic waters must be drawn along the 0° isotherm; 
to the south h\ the southern side of the ridges along the 600 metre curve. The boreal region ex- 
tends thus from far up in Davis Strait, where, however, it extends only in a very few places in to 
the coast of West Greenland, across the highest part of the submarine ridge into Danmark Strait, 
round the coasts of Iceland, including also the plateau between Iceland and the Faroe Islands, the 
Faroe Islands Banks, the western Scottish waters, and the North Sea and the Norwegian coast pla- 
teaus (vide charts). Practicalh' speaking, the region embraces all the coast banks of the waters in- 
vestigated, down to 600 metres, save for the upper 200 metres of the Greenland banks. 

On comparing the results here arrived at with the lines laid down in Appellof's' and v. 
Hofsten's-, 3 fundamental works on Crustacea and Echinoderms, we find that they agree very closely 
therewith. We have, however, here disregarded the mixed areas, which in the works referred to are 
strongly emphasised. The "boreo-arctic" area, where arctic and boreal elements appear in equal pro- 
portions, should strictly speaking doubtless comprise the upper parts of Store and Lille Hellefiske- 
banke, possibly also Fylla Banke, West Greenland, while the north Icelandic coastal region likewise 
seems to belong to the same. The second mixed area, which according to Appellof includes the 
southern parts of the North Sea, the English Channel, and the Irish Channel, should be characterised 
by a ver>- marked intermixture of southern, Lusitaniau or Mediterranean species. 

It has previously been pointed out that hydroids only penetrate in small numbers down beyond 
600 metres depth. It might therefore be objected that the southern boundary of the boreal region as 
against the Atlantic will in the case of other animal groups be found to follow a deeper curve than 
here indicated. In comparison therefore, we should also include arctic-boreal species of other animal 
groups which are more eurybathic. It will here suffice to refer to v. Hofsten's charts for Opluodcti 
sericeutu and Spiroiitocaris Gaimardii; they show the same features as the corresponding hydroid spe- 
cies, and the same southern limits for the boreal region at about 600 metres' depth. 

I 1906, Die dekapoden Crustaceen. Meeresfauna von Bergen, Heft 2 und 3. Bergen. 

= 1915, Die Echinodennen des Eisfjordes. Zoologiscbe Ergebnisse der schwedischen E.\pedition nach Spitzbergen 
190S. Teil II. Stockholm. 

3 1916, Die decapoden Crustaceen des Eisfjordes. Ibid. Teil II. vStockholm. 



i84 



HYDROIDA II 



One risk attaching to the insertion of the mentioned boreo-arctic and Lusitanian mixed areas 
lies on the one hand in the fact that by such further division, the whole arrangement is rendered 
less easy to survey and handle. If, however, other and more essential advantages were procured by 
so doing, we should naturally not hesitate to accept the biogeographical sub-areas in question But 
here a very serious difficulty makes itself felt, more particularly on considering the group of hydroids 
as a whole, to wit, the question of how far up in the boreal area — sensu laterior — the intermix- 
ture of southern elements takes place to such a degree that the waters concerned should be regarded 
as a mixed area. By way of illustration we may take the distribution of the families Plniujilariidir 




joo m boom. (ooo m. looom. 

Fig. XCIII. Finds of Plutnulariidae in the Northern .Atlantic. 

and Aglaopheniida^ the members of which without exception have their chief occurrence in warmer 
and more southerly waters, and must in the boreal region be regarded as southern visitors, even though 
some few of them, such as Nemertesia antennina, and Kirchmpaueria pmnata, may here and there 
occur in considerable numbers. We should note then, that Phimuhniidcr (fig. XCIII) which save for 
one or two exceptions belong to the upper 300 metres, are found ~ and found ver>- frequently - in 
the North Sea and along the west coast of Norway, including the Trondhjem Fjord, round the Faroe 
Islands, along the east, south and west coasts of Iceland; indeed, several species ha\'e even been met 
with several times on the borco-arctic Lille Hellefiskebanke in Davis Strait. Judging from the family 
PlumulariidcB then, we come to the result that the Lusitanian element plays a very prominent part 
m the heart of those areas which we have hitherto designated as the boreal; so much so indeed, that 
It would be necessary to place the greater part of the tracts concerned in the boreo-lusitanian mixed 
area if we were to follow Appellofs principles to their logical conclu.siou. Taking now again the 



HYDROIDA II 



ISS 



family Aghioplicnlidir (fig. XCIV) we must first of all bear in mind that we are here dealing with 
the hydroid family which contains most true deep-sea species, so that we get a picture essentially 
different from the previous one. Yet there are also various resemblances observable. The boreal 
bottom region is, as will be evident from the foregoing, a restricted part of the typical coast bank 
region which runs down to about 600 metres depth. Up in this region, Aglaoplicniida: penetrate more 
rarely, but are yet not infrequenth- met with in the North Sea and along the coast of Norway, and 
may even in certain places be character forms, as for instance in the deep parts of the Trondhjem 
Fjord, where there is mticli current. The numerous finds groujj themselves about the Wvville-Thom- 




Fig. XCIV, Finds of Aglaophrtuidae ill the Northern Atlantic. 

son ridge, and of these, about half lie, mirabile dictu, down in that jaart of the cold area which juts 
out into the Faroe Channel. In Danmark Strait, also, the finds are gathered about the top of the 
threshold, and distribute tliemsehes from here round the north side of Iceland. In Da\-is Strait, 
the finds are closest in tlie north-eastern part of the cul de sac running from the Atlantic Deep up 
the western side of Greenland to the north side of Lille Hellefiskebanke. In this manner then, tlie 
intermediate parts between the aforementioned areas, where the strong intermixture of Plumiilanidcr 
sets its mark on the fauna, are levelled out. And to be entirely consistent, we should perhaps also, 
in the Faroe Channel, include a lusitano-arctic mixed area. 

The data here given serve to show that the establishment of the mentioned mixed areas, the 
boreo-arctic and the boreo-lusitanian, is attended by considerable drawback.s. No boundary of any 
region, of course will ever be perfectly clear and sharp, especially in the case of bottom form.s. There 
are too many factors to be considered, with the result that the frontier as a matter of fact comes to 

The Ingolf-Expedilion. V. -. ^"^ 



1 86 



HVDROIDA II 



consist of a more or less broad belt, and such belts or mixed areas may under special circumstances 
attain relatively considerable extent, while in other places they may be quite narrow. We must also 
remember that the boreal reg^ion in itself is the mixed area par excellence, and has practically not a 
single species to itself, which makes it even more difficult to sa)- what mixture percentage should be 
taken as limiting the extra mixed areas, the boreo-arctic and the boreo-lnsitanian. The maintenance 

of these will as a matter of fact be 
to some extent a matter of arbitrary 
preference. 

The factors exerting principal in- 
fluence in the formation of the mixed 
areas are the positive transportation 
and the passive restriction of the at- 
tached organism to the spot once 
adopted. The latter factor presents no 
difficulty; if a hydroid colony has once 
settled down at a given spot on the 
l)ottom, then it cannot change its si- 
tuation, even though the conditions 
under which it is there called upon to 
live prove unfavourable. A submarine 
wave may have produced suitable con- 
ditions at the time of attachment, af- 
ter which a change for the worse sets 
in. If the colony manages to thrive 
in spite of this, it will then depend 
on its propagation whether the species 
liecomes indigenous or not. It is pro- 
bably the question of propagation which 
has prevented Flu miliar iidir and Ag- 
hiopluiiiida' from becoming indigenous 
in the Norwegian Sea area; save for 
a few species, they must evidently be 
constantly recruited from without. This renewal takes place in the case of certain species, which lack 
suitable active motive apparatus, by passive tran.sportation. The transport of grown colonies is here 
practically speaking out of the question; these animals, we know, attach themselves normally to the 
.sea bottom itself, or to other colonies already attached thereto. It is therefore larval transportation 
which plays the chief part'. How long the larval development takes in these forms before thev at- 
tach themselves to the bottom we do not know; probably the time varies,"^ being doubtless dependent 
upon external physical conditions; under certain circumstances it would seem that it mav extend over 
a very considerable period. 

' Cf. .'Vppellof 1905. Havbundens Dyreliv, Norges Fiskerier I, Norsk Havfiske. Bergen p. 114. 




Fig. XCV. Currents of the Norwegian Sea 
(after Natisen and H elland-Hanseu ). 



HVDROIDA 11 



The explanation of the distribntion in these two families must tlierefore be sought in the 
current conditions, and we here obtain a very good idea in the case of Aglaoplieniidw. The currents 
in Davis Strait have as yet l;)een only \-er>- little investigated, but we know that there is an atlantic 
current nio\ing up from the deep towards Store Hellefiskebanke and thus depositing larvae in the 
cul de sac before mentioned. In the case of the Norwegian Sea, the currents are better known. On 
glancing at the chart (fig. XC\') and comparing it with the occurrence of Aglaopheniida;^ the solution 
is at once apparent. An atlantic current runs northward in the eastern part of Danniark Strait and 
sends a branch thence along the north side of Iceland and then southward along the east coast; this 
branch will thus carry larvae from Danmark Strait and deposit them here and there along the coastal 
banks north and east of the island, where some few of them are able to develope further. This at 
once explains the scattered occurrence of AglaoplieniidiC in these waters. The main force of the 
northgoing atlantic current, however, is concentrated in the Faroe Channel, and here carries 
the larvae in over the Wyville-Thomson ridge. Along the north side of this ridge, then, we find the 
heaviest "rain" of exotic larvie in the Norwegian Sea, and here also the greatest percentage of indi- 
viduals prol)al)ly capalile of de\'eloping further, pro\ided they can stand the immersion in the icy 
waters of the cold area at all. A branch of the same current nnis southward along the east coast of 
Scotland and England, causing a scattered occurrence of Aglaophr)tiidcc able to develope in shallower 
water, sucli as species belonging to the genera Aglaoplu-iiia and Thrcocarpiis. Other larvie drift farther 
on with the main current, and sink to the bottom on the Norwegian coast plateaus, or the edges of 
the same, or are occasionalh- carried as far \\\> as Spitzbergen, whence several finds of Aglaopheniida; 
have been recorded, where offshoots from the Atlantic current break in over the plateaus in the shal- 
lower Murman Sea. 



It would be of no value here to group the species investigated according to the separate geo- 
graphical categories. Such arrangement has been made several times in recent works by Kranip 
(1914) and myself (1909 and later works). It should merely be pointed out that pureh' boreal hydroids 
are extremely rare, if indeed we can, after exhaustive investigation, maintain an\" such at all. 

We may now proceed to a closer comparison of the hydroid fauna as it appears in the areas 
represented by Greenland, Iceland and the Faroe Island.s. With regard to the two first-mentioned 
areas, surveys have recently been published by Kramp (1914), and Sicmundsson (1911); the latter, 
however calls for certain corrections, and there are also some few additions to be made. 

Of the species here dealt with, the following have been met with in West Greenland waters 
(species new to the area are indicated by a *). 



*Corync Lovcui 
Myriothcla phrxgia 
Tubularia iiidivisa 
Corxiiiorpliti groculaiidica 
* Bran cliiocc riant lilts rcuiformis 
? Clava inulficoniis 



Mo)iobrachiuiii t'arasitiiin 
*Hydracti>iia Sarsii 

— ecliiiiata 
^Perigoiiiinus abyssi 

— roscus 
Ell dt 7/ drill i/i ra tii i 'ii in 



In the previous chapters the name has erroneously been sjielt Lajoca. 



Eiidciidriuin aiinulatum 

— capiUarc 

Lafcea ditmosa^ 

— fruticosa 

— graciUinia 
Toichopoiiia obliqmim 

24* 



i88 



HYDROIDA II 



Grammaria serpens 
* — con/erta 

— ahietina 

— iinniersa 
Lie ford la piiuiafa 
Stegopoma plicatile 
Ctispidella Iniinilis 
Lafoeiiia inaxiiiia 
Cainpainilina fitrritn 
Calycella syn'iiga 
Tetrapoma qjiadrideutatuiii 
*Haleci7uii scii/iiii/ 

— ciirvicmile 

— vriirieafuiii 

— Id bras 11)11 

— fc lie I hi III 



Halechuii miiiutum 
*Polyphi III aria profunda 
Nemertesia antennina 
* Polytteviertesia gracillima 
Aglaoplienopsis eoriiiifa 
*Cladoearpus integer 

— foriiiosits 

Thecoea rpiis inyriopli \Uii in 
Sertularella fniiiarisca 

— Irieiispidafa 

— polyzonias 

— rugosa 

— tenella 
Diphasia fallax 

— ]\'(iiideli 
Dviiaiiiena piiiiiiln 



A biefiiiarin abiefina 

— filieitia 
Sertularia tenera 

— Fabricii 

— iiiirahilis 
Thiijaria fliiija 

— laxa 

— alfeniitlieea 
Ca iiipn lilt Id rid volu hilis 

— vertieilldta 

— groeiildiidiea 

— speciosa 
Caiiipaiiiildrid iiitcgra 
Laomeded longissiina 

— hydliiid 
Boiiiievielld graiidis 



By comparison with Kranip's list (1914) it must be noted, that the following species are 
svnonvms : 



Ga rveid orocu id 11 die d 



Perigoiiiiiius roscus 



Perigoiiiinus roseus 



Ildleciuiii Beaiii = Haleciiiiii seittuiii 

P/ininilaria groeiildi/died = Polyiieiiiertesia graeilliiiid 
Clddocarpus Holiiii = Clddoedrpiis integer 



New to tlie area are 
Sarsii, Perigoniiinis dbyssi. 

Of East Greenland 
Tubularia rcs^alis 
*Pcrigonimns abyssi 
* — roseiis 

Ell den driii in rd in eii in 
LafcBa friiticosn 

— grdeilliiiid 
Toichopoina obliqiiuin 
Graiinnarid serpens 

— dliietina 

— iinniersa 
Cuspidella Immilis 
La/oeina maxima 



thus in reality onl)- the five species Brdiicliioceriantlins renifonnis^ Ilydractinia 
Grannnarid conferta and Polypliinidria profunda. 



species, the material contains the following: 
Calycella syringa 
Tetrapoma qtiadrideiifatuin 
Haleciuin curvicaule 

— iimricatum 

* — Idbrosuin 

— tenelluin 

— Ill III II til III 

* Cld doi (irpus in teger 
Sertiihirrlld triciispiddtd 

— polyzonias 

* — tenella 



Diphasia fallax 
Abietinaria abietina 
Sertularia tenera 
Hydralliiiania falcata 
Thiijdrid til I if I 

— IdXd 

Cd iiipd 1 1 II Id rid vol It bills 

— vertieilldta 

— proeiilandiea 



— integrd 

Laoinedea longissiina 



HYDROIDA II 



189 



Taking into consideration the above noted synonyms, only three species are new to the area, 
viz: Halecium labrosuin^ Cladocarpus integer and Srr hilar clla tenella. It should here further be noted 
that the new investigations have especially augmented the number of species south of 70° N. The 
East Greenland waters between 60° and 70° N. seem to be very poor in hydroids, even right out on 
the slope towards the deep of the Frozen Sea, and the Atlantic deep. 

According to Kramp (1914) there are hitherto recorded 88 hydroids from Greenland. In the 
previous sections we ha\'e pointed out the following synonyms, which are given in the mentioned list: 



Coryiiiorpha grociilaiidica 

— is/a/idica 
Pcrigoiiinus rose us 
Garveia groenldtidiea 
Haleeiiim Beani 
Lafoea frittieosa 

— pociUu»i 

— grand is 
Sertiilarici polyzonias 

— gigd^iiea 

Phi III u la ria groe 11 la 11 dica 
A iiteiiniilaria aiiteiiiiina 
Cladocarpus cornutus 

— Hoi mi 



= Coryiiiorplia groenlandica 



Perigoiiiiiius roseits 



= Halecium scutum 

= Lafcra fruticosa^ forma geiiuiiia and forma graiidis 

I = Sertula ria polyzonias, forma lypica and ioxma. gigantea 

= Polyncmertesia gracillima 

= Ncmertesia antennina 

= Aglaopheiiopsis corniUa 

= Cladocarpus integer 



This means, then, a reduction of five in the number of species. On the other hand, the five 
new species from the West Greenland area are entireh- new to the fauna, so that the number of spe- 
cies is still 88, or, taking Lafcea fruticosa forma graiidis and Sertularella polyzonias forma gigantea 
as distinct species, the number is increased to 90. The recent studies have thus not greatly increased 
the number of species, nor was this to be expected. The greatest increment of species new to the 
fauna was to be expected in Davis Strait, and the few investigation stations made there by the 
"lugolf are entirely covered by the later expeditious with the "Tjalfe", the excellent treatment of 
which material has contributed in an essential degree to our comparatively close knowledge of the 
In-droid fauna in West Greenland waters. 

Passing on now to the fauna area of Iceland, we find in the material the following species 
belonging to this section: 



Coryiie Sarsii 
* — pusilla 
Alyriothela phrygia 
Tubularia piilclier 

— indivisa 

— larynx 



Coryiiiorplia nutans 
— glacialis 

* — groenlandica 

* Clava III u Iticornis 
*Hydractinia Sarsii 

— cchinata 



Bougainvillia conferta 
Eudcndrimn rameum 
— ranwsiim 

cap it la re 
La/cca duntosa 
— fruticosa 



I go 



HYDROIDA II 



Lafma gracillima 
Grammaria serpens 
— • able tin a 

— iinmersa 

Lictorella pijinafa 
*Zygophyla.\ biarmata 
* Stegopoma plicatile 
Ciispidrlla hiimilis 
Lafoehia viaxiiiia 
CalyccUa syriiiga 
HalecittDi Iialrciimm 

— Brai/i 

* — sciitain 

— airvicaule 

— iiiuricatniii 

— labrosiiiii 

— teiirlhtin 

— Ill i mil Kill 
Kirchnipaurria piniiala 
Pliiiiiiiliina setacea 

— Catharina 

Poly pill mar ia fnitescens 

* — flabellata 

* — profunda 



Nemertesia antennina 

— ratnosa 
Poly nemertesia gracillima 

* Halicornaria campanulata 
*Nematocarpics ramulifcrus 
*Aglaophciiopsis cor nit la 
*Cladocarpits integer 

* — forinosiis 

* — bicHspis 

* Til ecoca rp us in xriopliyllii m 
Serin la rella ta ma risen 

— tricuspidata 

* — amphoripera 

— polyzonias 

— Gayi 

— rngosa 
Dipliasia fallax 

— Wan deli 

— rosacea 

* — attcniiata 
Dynamena piimila 
A bietinaria abietina 

— piiciila 

— (■'') fusca 



Sertitlaria cupressina 

— ten era 

— Fa brie a 

— mirabilis 
Hydriillmania palcata 
Tliiijaria tliiija 

— loiicliitis 

— laxa 

* — alfcrnitJieca 

— arctica 

— carica 
Campanularia volubilis 
Cavipaniilaria verticillata 

— groenlandica 

— integra 

— Hincksi 

— Jolinstoni 
Laomedea flexiiosa 

— geniciilafa 

— longissima 

— Iiyaliiia 

— gracilis 
Bonnc7'iella prandis. 



An examination of Sasmundsson 's material and list (1911) will show that it contains the 
following: svnonvms: 



Clava sqiiamala 
Coryne vermiciilaris 

— fruticosa 
Syncorync eximia 
Syncoryne Sarsii 
Auliscus piilcher 
Amalthiea island ica 
Corymorplia gliicialis 
Eudetidriiim ramciiiii 

— rigidum ? 

Dicoryne confcrta 
Loom I -dea gela tin osa 
— longissima 



Clav, 



itilfic 



= Coryne piisilla 

= Coryne Sarsii 

= Tubitlaria piilclier 

= Corymorplia glacialis 



= F.iidcndr 



iiim rameum 



= Bougainvillia conperta 



=^ Laomedea longissima 



HYDROIDA II 



191 



La/or a pygmcpa \ 

— gracillima ] 



— pocillum 

— synniiefrica 

— fniticosa 
FilelliDii sfrpfiis 
LicforcUa Ln'iiisnii 
Scrfttlaria cuprrssina 

— argentra 

— p II mild 
Dipl/iisia fitsca 

— abictiiia 
A ntt'iiinilariii aiitrnuitia 

— rainosii 
Plumularia piniiata 

— gracilli)iia 

— frutesccns 
T/iecocarpKs mdiccilatiis 
Cladocarpus Holiiii 



= Lafcca gracillima 

^= Jjipra frjifirnxa forma genitiva and forma grandis 

= Graiiniiaria scrpnis 
= Zygophylax biarniata 

= Srrfidaria ciiprrssiiia 

= Dynaii/ri/i! piiiiiila 

= Abicfiuaria (?) pnsca 

= Abictiiiarin pliciila 

= N^fiiirrtrsia niitcnuiiia 

= — raiiiosa 

= Kirchnipaiirria piiiiinta 

= Polynevicrtesia graciUinia 

= Polyphimaria fnitcscriis 

= TIiccoca)pus )iiyriopli\Uiiiii 

= Cladocarpus integer 



The synouynis noted reduce the munber of species b\' 9; furthermore, Ssemuudsson (1902, 
191 1) notes Turris neghcta Lesson, which here probably represents a voting colonv of Clava mitlii- 
coniis, and Dipliira fritillaria (Haeckel) = Corytir prifillaria .Steenstrup, an aUogether luicertain species 
(cf. Part I, p. 23). Renewed investigations must also decide wliat species is concealed under the name 
Perigoiiiiiius rrpriis. Altogether, we have then to reduce the 90 species noted bv .Stemundsson to 
a certain 77. But the geographical details for these species are highly uncertain, as the determina- 
tion has on revision often pro\'ed erroneous. In the revised collections, for instance, we find under 
the old label ^'■T/nifaria loncliitis''' specimens of T/iuJaria lonc/iifis^ lliujarin Inxa, Thiijaria altcrnitheca^ and 
Thnjaria carica^ while under '■^Laoinedea flexiiosa" we find labelled, besides specimens actually belonging 
to that species, also others of I.aomedra gciiiciilata and Laoutcdca lougissiiiia. On the other hand, spe- 
cimens of Laomcdea loiigissiiiia are distributed under the names of Laoiiiedra pcx/iosa, Laomedea long- 
issijiia, and Laoii/edea gelatiiiosa — taking examples at haphazard. The details are apparent from the 
notes under the separate headings. Even though the detailed records thus leave much to be desired, 
we have nevertheless a pretty fair sur\-ev of the species comprised under the area as a whole. The 
investigations have now added the following 14 new species to the list: 



Corviiiorpha grotulaiidica 
Hydraclinia Sarsii 
Stegoponia plicatile 
Halcciitiii scutiini 
Polypluiiiaria /label lata 



Pohpliunarid profunda 
Halicornaria catnpanulata 
NetnatocarpHs ranniliferus 
Aglaopheuopsis cor fin fa 
Cladocarpus formosiis 



Cladocarpus bicuspis 
Serhilarclla ainphorifera 
Diphasta afteiiuafa 
Thuja rui alternitheca 



192 



HYDROIDA II 



We have thus reached a total of 91 species certainly known. The nature of the additions is 
not nninflnenced by the fact that the investigations were largely carried out on the deeper slopes of 
the coastal banks, so that southern and eurytherm species form the majority of the species thus added 
to the fauna list of the island. 

We now come to the fauna of the Faroe Islands area. The species from here which are included 
in the material cover the entire range of our present knowledge as to the hydroid fauna of this sec- 
tion. We have here the following 57 species: 



Coryne pusilla 
Tubiilaria indivisa 

— larynx 
Clava iinilticornis 
Meroiia conincopiae 
Boiigaiiri'iUia coufri'ta 
Pcrigaiiinuis re pens 
Ell dend rill III rn me 11 in 

— IVrighti 

— ca pillar c 
Lafaa duiiiosa 

— fruticosa 

— gracilliina 
Grainiiiaria serpens 

— (ibietina 
Calycclln syringa 
Ha 1 1 rill in Iialecinu in 

— sen III III 

— viiiricatuin 



Haleciiiin labrosiiin 

— te lie I III III 
Kirchenpaiieria pin nata 
Pill III II la ria Cat ha riiia 
Polypi n ma ria frntesceiis 
Nc inertcsia antenniiia 

— ramosa 

Ncmatoearpiis ramuliferits 
Cladoearpns forinosiis 
Thecoearpiis invriopliylliim 
Serin la rella la ma rise a 

— triciispidata 

— polyzonias 

— Gayi 

— tciiella 

— riigosa 
Dipliasia fallax 

— rosacea 
Dyiianieiia piniiila 



Abiel ilia ria able Una 

— Jilicula 

— (?) fusca 
Sertnlaria cupressina 

— ten era 
Hydrallmania falcata 
Thuja ria Ihnja 

— laxa 
Ca in pan u la ria volitbilis 

— verticillata 

— Integra 

— Hincksi 

— folinstoni 
Laoinedea flexuosa 

gciiiculata 

— longissima 

— hxaliiia 

— graeilis 
Bonneviella grand is 



Along the deepest portions of the slope of the banks, the following five were found: Tiibnlaria 
rcgalis, Corymorplia glaeialis, Corymorpha groeiilandica^ Lictorella pinnata^ and Sertnlarella inirabilis: 
save for the last but one, all of these belong to the cold area; finds lie so far out in the periphery 
that it is doubtful whether they .sliould really be counted as belonging to the fauna of the Faroe 
Bank. If \\x- do so, then we have up to now 62 species recorded from the Faroe Islands sec- 
tion, but the number will doubtless be increased by further study. We must at any rate expect to 
find the following six species at the F'aroe Islands, since they are found, and partly also frequent, in 
Iceland waters and round the British Isles: Coryne Sarsti, Corymorpha nutans, Hydractiiiia eehinala, 
Cuspidclla liitiiiilis, Plumnlaria setacea, and Dipliasia attennata. This, howe\-er probabh' by no means 
exhausts the list of species, and in particular we may expect to find more southern forms as more 
or less sporadic visitors to the Faroe Islands. 

A compari.son between the fauna of the three areas shows that the Greenland area includes 
II species not known from Iceland or the Faroe Islands. The.se are: 



HYDROIDA n iQ, 



Coryne Loveni Perigonhiuis abyssi Campannlina turrita 

Tubularia regalis — roseus Tctrapoma qtiadridentahim 

Braiichiocerianthus rcniformis Eitdcndrium aiinulafimi Campanularia spcciosa 

Moiiohrac/iiitTJi farasihivi ToicJiopovta ohliqintvi 

Of the species mentioned, however, Coryne Loveni is also known from the North Sea as far 
down as tlie Danish waters, and it wonld seem Hkely that it is identical with the polyp Coryne Jri- 
tillaria Steenstrup, and thus belongs to the Iceland fauna area. Perigonimus abyssi and Perigonimus 
roseus extend southward along the west coast of Scandinavia at any rate as far as Bohuslan; Euden- 
drium annulafuiii has been recorded both in Norwegian and in British waters, and Campainilina tur- 
rita has been found in Irish waters, near Belfast. In the case of these species it is thus natural to 
suppose that they will also prove to occur in the intermediate areas at the Faroe Islands and Ice- 
land. The geographical character of Braiicliioccriantlnis renifonuis is altogether unkiuiwu. We have 
then remaining, as peculiar to Greenland, the s])ecies Tithiilaria. regalis, Monobrachium parasitum, 
Toichopoiia obliquuiii, Tctrapoma qiiadridtii/atniii, and Cainpamdaria speciosa, high arctic or panarctic 
species which appear to be of particularly stenothermic character. 

A far more unexpected state of things is met with in the Iceland area. The characteristic 
species here are: 

Tubularia pulclirr Pluviularia setacca ' ' Sertularclla amphorifera 

Corymorpha nutans Polyphtmaria flabcllata Dipliasia attenuata 

— glacialis Halicornaria cavipannlata Ttmjaria carica 

Zygopliylax biarniafa Cladocarpns bictispis 

Among these there are, as far as our knowledge at present goes, two easterly, panarctic spe- 
cies, to wit, Corxmorplia glacialis and Thiijaria carica. These species thus characterise the Icelandic 
fauna area as the frontier tract for east-arctic species. Similarly, the occurrence of the Greenlandic 
Thujaria alfcrniflicca suggests that the area in question is also a boundar>- region for westerly, arctic- 
boreal species. The list given is, however, most striking from the many exotic warm-water .species 
which it contains. The Iceland fauna area has, as a matter of fact, at present several more such 
species than the Faroe Islands area. It would thus seem as if the influence of the warm atlantic 
area upon the southern slope of the Iceland grounds is more immediate. How far the Rockall Banks 
may be partly responsible for the somewhat less marked immigration of warmer atlantic species to 
the Faroe Islands area cannot be stated with certaint\-, but there are several indications that such 
might well be the case. 

The Faroe Islands area is distinguished b\- onl\- two species, Mcrona cornucopice and Eudendriuni 
/f >/>////, as against the two other areas; these two species contribute, however, but little to the char- 
acterisation of the waters in question as we know them at present. The most striking feature 
of the true Faroe Bank area is another, negative character, to wit, the lack of high arctic or 
panarctic species. Only deeper-living arctic species such as Tubularia regalis. Corymorplia glacialis, 
Corymorpha grocnlandica, Grammaria immersa. Stcgopoma plicatile, and Scrfularia Fabricii verge now 

Tlie Ingolf-Exptdition. V. -. *^ 



TO. HYDROIDA II 

194 



and again on to the deepest parts of the Faroe Bank, where they rise from the cold area at the 
eastern slopes of the ground. 

The community which is characterised by the last-named species, and which further includes 
Lafcea fruticosa forma grandis, Lafma gracilliiiia forma clegantula^ and ScrtulareUa polyzonias forma 
gigantea, has its home throughout the whole of the arctic regions; farther to the north, we find it in 
shallower water, in the southern parts of the cold area in deeper; here also, it penetrates out to the 
Wyville Thomson ridge in the Faroe Channel, where warm atlantic water-masses present a barrier 
to its further progress. Only a single iind oi Myrioihela phrygta has been made on the southern slope 
of the Wyville Thomson ridge. These species thus characterise the Norwegian Sea Deep, and show 
the marked difference between it and the Atlantic deep sea region. The limit of their occurrence here 
in the south follows on the whole very closely the 0° isotherm. 

True these species may at times, in higher latitudes, occur in water layers of higher tempe- 
rature, but this can have no effect on the limitation of the cold area as a whole against the boreal 
and atlantic tracts. A biogeographical peculiarity is seen in the Trondhjem Fjord, where hydrogra- 
phical conditions of an atlantic character prevail, nevertheless we here find Myriotlicia phrygia, Tii- 
bularia rcgalis, CoryiiiorpJia gronilnitdica, and Stcgopoma plica file thriving excellently; indeed, Tiihida- 
ria rcgalis^ and Stcgopunia plicntilr even appear as local character forms in the otherwise purely atlantic 
Lophohelia-hiocoe.TiozQ. This can apparently only be explained by regarding the species as relicts in 
tlie fjord, which have been able to adapt themselves to altered conditions there. This exception, how- 
ever, cannot alter their general character as arctic species. 

On the other hand, we find in the material also species which are not able to penetrate beyond 
the limits of the warm atlantic water-layers, and which are thus entirely lacking in the boreal region. 
These species emphasise still further the marked difference between the fauna of the Atlantic abyssal 
region and the cold area. We may here in particular point out Grammaria confcrta. Zygophylax 
biariiKitu, Polyplniiiaria profunda, and ScrtulareUa amphori/era, typical representatives of the warm 
atlantic deep-sea fauna. The finding of these so far to tlie north shows us on the one hand how 
uniform the fauna must be throughout the deep region of the Atlantic, but also, on the other hand, 
lu)w little we yet know as to the geographical distribution of the bottom fauna, and what great and 
tempting tasks still await the investigator in thoroughly elucidating the question of Ijottom fauna 
even here in the North Atlantic. 



HYDROIDA II 



195 



V. List of the genera treated, and type-species. 



(Nomina conservandaj. 



Cory lie, G a e r t ti e r 
Myriothela, j\I. vSars 
Tubularia^ Lin lie 
Coryniorplia. M. Sars 
Braiicliiocrriaiitlius. Mark 
t lava, G m e li n 
Merona, Norma n. 
Monobracliiiiiii, M e r e s c li k o \v s k y. 
Hydractiiiia. \' a n B e 11 e d e n. 
Botigaiiivillia . Lesson. 
Perigonimus. M. Sars. 
Eiidcudriitui. Eh re nljerg. 

Lafcca, L a m euro u x. 
Toichopoma, Levinsen. 
Graniinaria, Stim ps o n. 
Lie f or f 11(1 . A 1 1 ni a n. 
Zygophylax. O u e 1 c h. 
Stegopovia . L e \' i n s e n. 
Cuspidella, H i n c k s. 
La/omia. ^l. Sars. 
Campanuliiia. van Beneden. 
Calycclla. Hincks. 
Tetraponia, Levinsen. 
Halecium, Oken. 
Kirc/ienpaiteria, J i c k e 1 i. 
Pluiiuilaria. Lamarck. 
Polyphiiiiaria, G. O. Sars. 
Keiiiertesia, L a m o n r o u x. 
Polyneniertesia. no\'. 
Halieornaria (Busk). 
Neinatocarpiis, nov. 
Aglaop/ienopsis, F e \v k e s. 
Cladocarpns, All man. 
Theeocarpiis, N n 1 1 i n g. 
Aglaoplieiiia . L a m o u r o u x. 
ScrtularcUa. G r a }■. 



Cory lie pusilla. Gaertner 1774. 
Lucernaria plirygia, F a b r i c i u s 1 780. 
Tubular ia indivim, Linne 1758. 
Coryniorplia nutans, M. Sars 1835. 
Monocaulus iiiiperator, A Urn an 1888. 
Hydra luulticornis, Forskal 1775. 
Tubiclava cornucopiae, Norman 1864. 
Moiiobracliiuvi parasitum, M ereschkowsky 1877. 
Alcyonium echiimtuiii, Fleming 1828. 
Endendrium ramosuiii. van Beneden 1844. 
Perigoiiiiiius iiiiiseoides, M. vSars 1846. 
Tubnlaria raiiiosa, Linne 1758. 

Campanularia diiiiiosa, Fleming 1820. 
Calycella obliqua, Hincks 1874. 
Campannlaria abietina, M. Sars 1851. 
Lafoea pinnata. G. O. Sars 1874. 
ZygopIt\lax profunda, Onelch 1885. 
Calycella plieatilis, G. O. Sars 1874. 
Campanularia liumilis. Alder 1863. 
Lafoiiina tenuis, M. Sars 1869. 
Campanuliiia tenuis, van Beneden 1847. 
Sertularia syringa, Linne 1767. 
Calycella quadridentata, Hincks 1874. 
Sertularia halecina. Linne 1758. 
Sertularia pinnata, Linne 1758. 
Sertularia setacea, Linne 1758. 
Polypluinaria flabellata, G. O. Sars 1874- 
Sertularia antennina, Linne 1758. 
Plumularia gracilliina, G. (J. Sars 1873. 
Halieornaria hipinnata, Allman 1876. 
Halieornaria raiimlifera. Allmann 1874. 
Aglaophenopsis Iiirsuta, Fewkes 1S81. 
Cladocarpus forviosns, Allman 1S74. 
Sertularia niyriophylluin. Linne 1758. 
Sertularia ////w^/. Linne 1758. 
Sertularia /f'/)'COT//rtJ, Linne 1758. 

25* 



196 



HYDROIDA II 



Diphasia, L. Agassiz. 
Dynamcna, L, a m o 11 r o u x. 
A bictinaria, K i r c h e n p a 11 e r. 
Sertiilaria, Lin 11 e. 
Hydrallmania, Hi neks. 
TJmjaria, Fleming. 
Campanularia, Lamarck. 
Laoniedea. Lamonroux. 
BoiincvicUa. B r o c h. 



Sertularia rosacea, Linne 1758. 
Sertularia ^«;«//«, Linne 1758. 
Sertularia abietina, Linne 1758. 
Sertularia cupressina, Linne 1758. 
Sertnlaria yrt/ca/ff, Linne 1758. 
Sertularia tliiija, Linne 1758. 
Sertularia vobibilis^ Linne 1758. 
Laoi/iedea Jiexuosa, Alder 1856. 
Campannlaria ^r(7;/(//>. A 11 man 1874. 



Trondhjem, 24. — VI. — igiy. 



LITERATURE. 



1. Agassi:, Al. (1S65): Illustrated Catalogue of the Museum of Coiiipaiatis'e Zoology at Harvard College. North Ainericau 
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2. Agassiz. L. (1S60— 1S62): Contributions to the Natural Historv' of the United .States of America, Second Monograph, vol. 3 
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7. — (1863): Supplement to a Catalogue of the Zoophytes of Northumberland and Durham (Trans. Tyneside Nat. Field 
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15. — (1SS8): Ibidem. Part 2. The Tubularinse, Corymorjihinae, Campanularinae, Sertularin;e, and Thalamophora (Rep. scient. 
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igS 



HYDROIDA II 



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200 HYDROIDA II 



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INDEX 



Adietinan'a abietma II ///, 1 88, 190, 192, 196 

— filiciila II 1:8, iig, 129, 1S8, 190, 

191, 192 

— {>.)fusca 11/20, 144, 190, 191, 192 

Aglaophenia bicuspis II S9 

— foriiiosa II 86 

— Integra II 82, 83 

— plnma II 195 

— ttibnlifera W 94 

Aglaophenopsis cormita II 63, ^^y 188, 189, 190, 

191 

— hirsuta II 195 

— pharetra II Ho 

— I'eirillf II 81 

Alcyonuim echinatum I 46. II 195 

Amalthcca islandica I 29, 30, 32, 33. 11 190, 

191 

— uvifera I 30 

Antennularia aiitennina II 64, 189, 191 

— ramosa II 56 

— tetrasticha H 63 

— variabilis II 66, 68 

Auliscus pulchei 1 22. II 190 

Bonneviella grandis II lyj, 188, 190, 192, I96 

Botigainz'tllici conferta I S'^^- II 1S9, 190, 192 

— ravtosa II 195 

Branchiocerianthus iinpi'rator II 53, 175, 176, 177, 195 

— n. sp. S techo w . II 177 

— reniformis II 176, 179, 1S7, 188, 193 

— iirceohis II 175, 177 

Calycella obliqua II 15, 195 

— plicatilis II 26, 195 

— quadriclentata II 34. 195 

— syiiiiga II 10, II, 32, 188, 190, 

192. 195 
Campaiiulaiia abietina II 18, 195 

— caliculata II 159 

— compressa U 151, 159, 161 

— dumosa H 7. i95 

— fruticosa II 12 

The Ingolf-Expedition. V. 7. 



Cnmpanulniiii gracillima II 9 

— grandis II 1 73. 

— • grorttlandica II t^y, 

— Hincksii II 158, 

— huiiiilis II 29 

— liittgra . II 151, 

— Johnstoni II 155, 

— lobnlii II 157 

— luagniftca II 158, 

— Ritteri II 159 

— serpens II 16 

— spt-cwsa II IS^-, 

— vertkiUata II 152, 

190, 

^— vohtbilis II IS3< 

196 

Campaniclava cUouis I 38, 

Cam/>ntuiUnij fenuis II 195 

— tJirn'ta II J^t 1 

Cladocarpiis biciispis II Sg, 

— catnpanulatus II 72 

— comprt'ssits II 87 

— cornutus H 77. 

— crenulatus II 85, 

— Diana II 57, 

— flexuosii-s II 82 

— formosus II S$, 

195 

— Holmi II 82, 

191 

— integer II 73, 

191 

— paradisens H 86, 

— Pourtalesi II 82, 

— Sigma II S9 

— tenuis II 82 

Clava leptoslyla 1 40 

— tmilticornis I lo, 

I go, 

— parasitica I 38 



196 

162, 188, 190 

162, 190, 192 

95 

759, 188, 190, 192 

163, 190, 192 

159 



18S, 193 

15s, 162, 164, 188, 

192 

1 58, 1 88, 190, 192, 

42 

88, 193 
190, 191, 193 



1S9 
86 
90, 182 

iSS, 190, 191, 192 

83, 84, 1 88, 1 89, 

Sz. 1 88, 189, 190 

89 
S3, 84 



jA', II 179. 187, 189, 
192' '95 

26, 



202 



HYDROIDA II 



Clava squamata 1 38. II 190 

Clytia bicopliora II 163 

— Johnstoni II 163 

Corymorpha gJaciahs I 27, 28, J2. II 175, l8g, 

190, 192, 193 

— groenlandka I 21, 27, JJ. II i'}4, 175, 

182, 183, 187, 1S9, 191, 

192, 193. 194 

— mitans 1 30, j;. II 174, 190, 192, 

193. 195 

— penduLa II 175 

— Sarsii 1 29 

— spitzbergensis I 33. 36 

— vardoensis I 29 

Coryne brevicornis I 13 

— eximia I 16 

— fritillaria I 23. II 191, 193 

— fruticosa I 16. II 190 

— Himksi I I 3j iS 

— sp. aff. Hincksi I ;,V 

— Love'm I 13, /5, 23. II 1S7, 193 

— pusilla I 13, /(). II 179, 189, 190 

192. 195 

— Sarsi I 13, 14. n 189, 190, 

192 

— vermicularis I 16. II 190 

Cryptolaria conferta II 17 

Cuspidclla humilis II 29, 188, 190, 192, 195 

Dicoryne conferta I 50. II 190 

Jiiphasia alata II n^ 

— iillenuaia II //j, igo, 191, 192. 193 

— fallax II 97, 7o5. 111,113, if'S. 

190, 192 

— f'lSCII II I<ji 

— inirabilis 11 i-^-^ 

— rosacm II ^j^ 109, 112, 190, 192, 

196 

— tainarisca II 96 

— Il'imdr/i II i„g^ I JO, 7/7, 188, 190 

Dytinmena pumila H ,,5, ,33, i-g_ jSo, 181, 

188. 190, 191, 192, 196 

— taniarisca II 96 

— tubuliformis 11 132 

— unilateralis II 127, 129 

EudendrhiDi mitmlatiim I 6/. II 187, 193 

— arbuscula I 60 

— capillare 1 61. II 187, 1S9, 192 

— caricum I 5S 

— conferta I 50 

— raccmosum I 60 

— rameum I 57, 60. II 1S7, 188, 189, 

190, 192 

— ramosum ' 57. 58, 59- H 189, 195 



EtidcndrUtni repens I 52 

— rigidum? I 58. II 190 

— vaginatum II 2 

— ]Vrighti I S, 57, (5o. II 179, 192, 

193 

Filellum serpens II 16, igi 

Garveia groeulandica I 54. II 1S8, 189 

Gonothyrtea gracilis II 170 

— h3-alina II 169 

— Loveni II 170 

Grnmmaria abietina II 6. 16, 7.5, 22, 151, 188. 

190, 192, 195 

— conferta II '7, 179, 182, 183, :S8, 

■» 194 

imiiwrsa II 20, 21, 22, 188, 190, 

193 

— robusta II 18 

— sca?idens II 16, 21 

— set-pens II ilS, 188, 190, 191, 192 

Phileciuni Beani II 37, j5, 40, 41, 1S8, 189, 

190 

— crinis II 49 

— curvicaule 11 4/, 188, 190 

— halecinitin II J(J, 39, 40, 41, 190, 

192, 195 

— labrosutti II 4S, 47. 1S8, 189, 190, 

192 

— ininiitum II 35, 49, ^o, 188, 190 

— mirabile II 42, 43 

— muricatum II ,^J, 47, 181, iSS, 190, 192 

— nnmttii II 49 

— ornatum H 36 

— repens II 42 

— Schneideri H 49 

— scutum II 37, J5, 188, 189, 190, 

191, 192 

— telescopicinn II 51 

— tenelhim II 46, 51, 188, 190, 192 

— textum II 46, 49 

Halicornaria hipinnata II I95 

— Ciimpanulata II 72, 87, 190, 191, 193 

— • Integra H 83 

— pluma II 74, 75 

— raniulifera II 74, 75, 195 

Hebella pocilluni II 6, 14 

Hydra niulticornis I 38. II 195 

— squamata I 38 

Hydrtictmia Allmani I 44 

carica I 44, 48 

— ■ rarnea I 45 

echimita I 44, 46- II 1S7, 1S9, 192, 

■195 

— fal/ax I 45 



HYDROIDA II 



203 



Hydractinia hnmilh 1 44 

— Jilichaelst-ni I 44 

■ — niimita 1 4S 

— monocarpa I 46. 48 

— ornata I 44 

— Sarsii 1 44, 45, 4^- 1' i^7' iS^S, 

189, 191 
Hvdrallmania disians II 137 

_ falcata II /J5. 18S. 190, 192, 196 

— franciscana II 137 

Hybocodon Christitiae 1 23 

Kirchenpaueria elegans II 53 

— pinnain II 5J- 1S4. 190, 191, 192, 

195 
Lafaa dumosa II 7, II 187, 189, 192, 195 

— fridicosa II 9, 10, ;.', 187, iSS. 1S9, 

191, 192, 194 

— gigantea II i73 

— gracilhma II 9, 13. 34. lS7, 188, 190, 

191, 192, 194 

— grandis II 12, 13, 15, 189 

— pinnata II 22, 24, 195 

— plicatilis II 26 

— pocillum 11 12, 13, 14. 1^9- '91 

pygmtea II 9, 'o. "> 3=, 34- 191 

— syniuietrica II 12, 13, 15, 191 

Lafol-ina maxima II 29, Jo, 188, 190 

— tenuis II 29, 195 

Lampra arctica I 3i' 3^ 

— atlantica I 31, 35 

— purpurea I 3'> 35 

— socia I 31, 36 

Laomcdea Clarki II 17° 

— dichotoma II 164 

— pxtiosa 16. II 5, 151. 15^. I53> 

16s. 166, 16S, 169, 179, 

190, 191, 192, 196 

— gdatinosa II 168, 190, 191 

— gemculata II 165, 166, 1 79. 190, 191. 

192 

— gracilis II '70, 190. 192 

— hyalina II i6g, 171, l88, 19"- '92 

— longissima II 165, 166, 188, 190, 191, 

192 
Loveni II 168, 169, 170 

— sargassi 11 15^ 

Lictorella antipathcs II 23 

— halecioides II 22 

— Levinseui II 24, 25, 191 

— pinnata II -'-', 25, 94, 188, 190, 

192- 195 

Lovenella clausa II 34 

Luccrnayia phrygia I 19- II I95 



Mfrona cormicopiae 1 41). II 192, 193, 195 

Monobraclmim parasiticuin I 42 

— parasttum I 43. II 187, 193, 195 

MonocauUis glacialis I 29, 32. II 175 

— groenlandica I 29, 33. II 175 

— imperator II 53, 175, 195 

Monocorync gigantea I 12, 18 

Myriot/iela arctica I 19 

— Cocksi I 20 

— mitia I 20 

— phrygia I ig, 27. II 182, 183, 1S7, 

189, 194, 195 

Nematocarpus ramuliferus II 74, 77, 190, 191, 192, 

195 

Nemcrtesia antennina II 63, 64^ 67, 180, 184, 

18S, 189, igo, 191, 192, 

195 

— Can/it/ieca II 63 

— ramosa II 63, 64, 65, 06, 190, 

191, 192 

— testrasticha H 63 

Obelia flabellata II 152, 167, 169 

— geniculata II 152, 166 

— longissima II 167, 169, 170 

Ortiiopyxis caliculata IF 159, 160 

— couipressa II 15I1 I59 

— everta II 151 

Pacltycordyle M'eismaiini I 4 

Perigoninuis abyssi I 53. II 1S7, 188, 193 

— Cor a I 5 1 

— Georginae 1 5^ 

— muscoides I 52. II 195 

— repens I 51, 5-'. 11 191, 192 

— roseus \ 5J- " 187. 18S, 1S9, 193 

Fliiniiilaria alternata 11 57 

— Catharina W $6, 190. 192 

— caulitheca 11 63, 68 

— Clarkei II 57 

— frutescens H 59- '91 

— geminata H 57 

— gracillima II 69, 70, 71, 191, 195 

— groenlandica II "lO, 7'- 188, 1S9 

— pinnata H 52. 53. i9' 

— profunda II 60, 62 

— sctacea H 53. S5, 190. '92. '93- 

■95 

— tubulifera H 93 

Podocoryne camea 1 45 

Sarsii I 45 

Polynemertesia gracillima H 7". 18S, 190, 191, tgS 

Potyplumaria flabellata H 59, 61, 190, 191, 193, 

195 

— frutescens II 59. 60. 190, 191, 192 

26" 



204 



HVDROIDA II 



Polyphimaria profiiii'fn II 60, 179, 1S2, 183, 188, 

190, 191, 194 

Rhizoragium roseum I 54 

Schizotricha bifurca .... . . II 69 

— antarctica II 69, 70 

Selaginopsis altemitheca II 143 

— arctica II 145 

— fuSCa II y20 

— mirabilis H 133 

Sertularella amphorifera \\ joo, 179, 182, 1S3, 190, 

191, 193, 194 

— amphorina u 100 

— fusiformis \\ ,04, /05 

— '^''y' II 102, 190, 192 

— gigantea n joi, 1S9 

— peUucida n ,04 105 

— polyzonias n gS, 101, 104, 18S, 189, 

190, 192, 194, 195 

— rugosa II 106, 179. 1S8, 190, 192 

— tamarisca II 95, p6, loS, 18S, 190, 192 

— tenella jj ,0^^ jq^^ jgS, 189, 192 

— trkuspidata \\ 98, 100, iSi, 1S8, 190, 

192 

SeitnLaria abietina jj j j y jq^ 

— alata II 11^ 

— albimaris u jjy 

— antenniua n 64, 195 

— arctica j, ,^2, ,,7^ ,^6 

— argentea n ,,,^ ,,^ j,^^ j^j, 126, 

127, 128, I2g, 191 

— articulata n j ,g 

— atteiiuata ji j , , 

— Birul<r ,[ ,22, 126 

— cupressina n J22, ,24, 128, 129, 131, 

132, 190, 191, 192, 196 

Dijmphna; jj ,27, 12S 

Fabrich n ,22, 123, 130, 18S, 190, 

193 

— f^lll^^ta U 1^5^ igg 

— f^l'ax II los 

— filicula I, ,,g 

— frutescens \\ eg 

— f"sca II ,2(, 

— fusiformis n ,„r 

— Gayi II J02 

— geniculata n jge 

— halecina n 35, jg, 

— Helleri „ 55 

— inflata n ^^^ 

— lonchitis \\ j .g 

— longissima n 167 

— mirabilis II 122, 123, 133, 188, 190, 192 

— inuricata II 43 



Sertularia niyriophyllum II 92, 

— piiinata II 52, 

— pluma II 195 

— plumosa . . II 122 

— polyzonias H loi, 

— pumila II 115, 

— robusta II 122 

— rosacea II H2, 

— rugosa. II 106 

— setacea II 55. 

— syringa II 32, 

— tamarisca 11 96 

— tenella H 104 

— tcnera II 122, 

190, 

— Thonipsoni II 122, 

— thuja II 139 

— Tol/i ; II 122 

— tricuspidata II 98 

— (?) tiiiuhforiiiis 11 /J2, 

— Tfgu- II 122 

— verticillata II 155 

— volubilis II 153, 

Stegopoma caricuni II 26, 

— fastigiatuni II 27 

— pticatile I 21, 

190, 

Stylactis arctica I 45 

— Sarsii I 45 

Syncoryne eximia II 190 

— Loveiii I 15 

— mirabilis I 16 

— ramosa I 15 

— Sarsii I 13. 

Tetrapoiiui quinlridentatum II 34^ 

Tliecocarpus myriophylhtm II 74, 

192, 

— radicellatus H 93, 

Thnjaria albimaris II 122 

— altfniithcca II 143^ 

— arctica II 122, 

— argentea H 122 

— articiilcita H 142, 

— Birulje II 122 

— corica H 148, 

— cupressina U 122 

— distans ; n 14^ 

— sp. aff. distans II 148 

— Fabricii H 122 

— hippuris H 141 

— sp. aff. hippuris W 141 

— Hjorti II 142 

— immersa n 142 



'95 
53. 195 



195 
191, 1 96 



1 96 

195 
195 



123, 127, 135. 188, 
192 
127 
196 



182 



,196 ' 

27, 36. II 26, 188, 
191, 193, 194, 195 



II 190 

188, 193, 195 

g2, 188, 190, 191, 

195 
191 

188, 190, 191, 193 
129 

143, 146, 147 

190, 191, 193 



HYDROIDA II 



205 



Thiijaria inflata 

— kolaensis. . . . 

— laxa 

— lonchitis 

— pectinata. . . . 

— pluniosa .... 

— robusta 

— saliconiia . . . 

— tenera 

— Thorupsoni. . 

— thuja 

Tolli 

— tubuliformis . 

— variabilis .... 

— Vegae 

Toichopoma obliquum . . 
Tubiclava cornucopiae 



1 122 
I 146 
I 140, 142. 147. iSS, J90, 

191, 192 

1 142, 143, 144, 145, 

146, 19a, 191 
I 146 
I 122 
I 122 
1 120 
I 122 
I 122 
1 !3g, 141, 180, 188, 190, 

192, 196 

I 122 

I 132 
I 14s, 190 

I 122 

1 15, 187, iSS, 19?. 195 

1 40. II 195. 



Titbitiaria Christinae I 23 

— cornucopia I 21 

— coroiiata I 26 

— hiiiiiilis I 26 

— itulivisa I 6, 8, 24, 26, 30, 55. 

II 187, 189, 192, 195 

— larynx I 8, 57. II 189, 192 

— ohliqua 1 24 

— prolifer 1 23 

— pulchtr . 1 22. II 189, 190. 193 

— ramea I 57 

— ramosa I 59. II 195 

— rrgalis 16, 8, 24, 26, 30, 55. 

II 188, 192, 193, 194 

— variabilis I 25 

Turns neglecta II 191 

Zygophylax armata II 25 

— biarmata W 24, 179, 182, 183. 190, 

191, 193. 194 

— profunda II 195 



ERRATA. 



Part I pag. 6, line lo stands: he/eroinedusoj'd, read: cryptomcdusoid. 
Part II pag. 2 and following: Lafoeidae, Lafoea, read: Lafaidai\ Laf<ea. 
Part II p.ig'. 99, text, line 2 stands: From there is penetrates, read: From 
there it penetrates. 



Plate I. 

Fig. I. Campantilaria inlegra. Part of median longitudinal section showing basal part of h\dranth 
and inner thickening of hydrotheca wall, to the upper side of which the hydranth is attached. 
No trace of diaphragm whatever. Specimen from Herlo, near Bergen, fixed in picrin-subli- 
mate-acetic acid (after Rabl), coloured with Delafield's h^Ematoxyline — \'an Giesson. 
320/1. 

Fig. 2. Branchmcermnthus reniformis. T>-pe specnueu from "Ingolf St. 28. Nat. size. 

Fig. 3. Braiicliiuccria)ttliiis reniforviis. H\-dranth seen from below. 2,1. 

Fig. 4. Branchioceriantlms reuifortnis. Hydranth seen from above. The richly folded gastral endoderm 
distinctl}- visible through the large oral aperture. 21. 

Fig. 5. Branchiocerianthus refu/orinis. Primary branch of a blastostyle, showing method of ramifica- 
tion. The outer, grape-like swellings are close collections of quite small incipient gonophores. 
30 X 



The Ingolf Expedition, V, 7. 



Broch: Hydroida. Plate I. 













Br.v-h Hoi Ol phot. 



Ljusir A. B. Lagrelius & Weslphil. Stockholm 



THE IN GOLF-EXPEDITION 



1895 1896. 



THE LOCALITIES, DEPTHS, AND BOTTOIWTEMPERATURES OF THE STATIONS 



Station 
Nr. 



I,at. \. Loiis.-. \V. 



Depth 




1 


111 


Bottom- 


Station 


Daiiisli 
fathoms 


temp. 


I Nr. 



I.at. N. Lon".\V 



Depth 

in 
Daiiisli 
fathoms 



Bottom- 
temp, r 



St.ition 
Nr. 



I,at. N. I.oil- W 



Depth 

ill Bottom- 
Danish temp, 
fathoms i 



3 

6 

7 
S 

9 

lO 

II 

12 

r3 
U 
15 
i6 

17 

iS 

19 
20 
21 
22 
23 



62° 


30 


63^ 


04 


63° 


35 


64° 


07 


64° 


40 


63° 


43 


63^ 


13 


63° 


56' 


64° 


18 


64° 


24' 


64° 


34' 


64° 


3«' 


64° 


47' 


64° 


45' 


66° 


IS' 


65° 


43' 


62° 


49' 


61° 


44' 


60° 


29' 


58° 


20 


58° 


01' 


58° 


10' 


1 60° 


43 



8° 21 

9° 22 

10° 24 

11° 12 

12° 09 

14° 34 

15° 41 

I 24° 40' 

I 27° 00 

28° 50 

31° 12 

32° 37' 

i 34° 33 

' 35° "5' 

25° 59' 

26° 58 

26° 55 

30° 29 

34° 14' 

' 40° 48 

44° 45' 

48° 25 

56° 00' 



'32 
262 



1 55 

9'J 

600 

136 I 

I 

788 I 
1300 
1 040 

622 

176 

330 

250 

745 
1 135 
1566 
1695 

1330 ! 
'845 I 

Only tile 

Phiiiktou Nftl 



5 .3 
2°5 

7°o 

4°5 
6°o 
5°8 
3°5 
l°6 

o°3 
3°o 

4°4 

-o°75 

6°i 

3°4 
3°o 

2°4 

r°5 

2°4 

i°4 



24 
25 

26 



28 
29 
30 
31 
32 
33 
34 
35 
36 
37 
38 
39 
40 

41 
42 
43 
44 



63° 06' 
63° 30 
63° 5" 
63° 57 
64° 37 
64° 54 
65° 14 
65° 34' 
66° 50' 
66" 35 
66° 35 
67° 57 
65° 17 
65° 16 
61° 50' 
60° 17' 

59° I 
62° 00' 
62° 00' 

61° 39 
61° 41 
61° 42 
6i°42 



56" oq' 

54° 25' 
53° 03' 
52° 41' 
54° 24' 
55° 10' 
55" 42' 
54° 31' 
54° 28' 
55° 54' 
56° 38' 
55° 3"' 
54° t7' 
55° 05' 
56° 21' 

54° 05' 
51° 05' 
22° 38' 
21° 36' 
17° 10 
10° 17' 
10° II' 
9° 36' 



"99 

.582 
136 

34 
109 

393 

420 

68 

22 

88 

318 

35 

55 

362 

1435 

1715 

1870 

865 

S45 

1245 

625 

645 

545 



2"4 



o°6 

3°8 
3°5 

0°2 

i°05 

i°6 

3°9 

3°6 i 

'°5 

■ °4 

■°3 

2°9 

3°3 

2''o 

o''4 

o°o5 

4°8 



45 
46 

47 
48 

49 
50 
51 
52 
53 
54 
55 
56 
57 
58 

59 
60 
61 
62 

63 
64 

65 
66 

67 



61° 32 
61° 32' 
61° 32' 
61° 32' 
62° 07- 
62° 43' 
64° 15' 
63° 57' 
63° 15' 
63° oS' 
fi-° "-' 
64° 00' 
63° 37' 
64° 25' 
65° oo' 
65° "9' 
65° 03' 
63° i8' 
62° 40' 
62° 06' 
61° 33' 
61° 33' 
61° 3o' 



9" 43 
1 1 ° 36' 

■3° 4"' 

15° I r 
15° 07- 

"5° 07' 

14° 22' 

13° 32' 
15° 07' 
15° 40' 
15° 02' 
15° 09' 
13° 02' 
12° 09' 
11° 16' 
12° 27' 
13° 06' 
19° 12' 

19° o.S' 
19° 00' 
19° 00' 
20° 43' 
22° 30' 



643 
720 

950 
1150- 
1 120 
ro2o 
68 

420 

795 
691 

3>6 

6S 

350 
211 

310 

124 

55 
72 
800 
1041 
1089 
112S 
975 



4"i7 
2°4o 

3°23 
3°i7 

2°9I 

3° '3 

7°32 

7°87 

3°o8 

3°9 

5°9 

7°57 

3°4 

oOS 

o°i 

0°^ 

o°4 

7°92 

4°o 

3°< 
3°o 
3°3 



Station 
Xi. 



Lat. N. Lon^.W 



Depth 

in Bottom- 
Danish temp, 
fathoms 



Station 
Xr. 



Lat. N. Long.W 



Depth 

in 
Danish 
fathoms 



Bottom- 
temp. 



Station 
Nr. 



Lat. N. 



Long. W. 



Depth I 

in ; Bottom - 
Danish temp. 
fathoms 



S2 

«3 



,S6 
«7 

ss 

89 

90 

9' 



68 


62° 06' 


22° 30' 


69 


62° 40' 


22° 17' 


70 


63° 09' 


22° 05' 


71 


63° 46' 


22° 03' 


72 


63° 12' 


23° 04' 


73 


62° 58' 


23° 28' 


74 


62° 17' 


24° •,(>■ 




61° 57' 


25° 35' 




61° 28' 


25° o6' 


75 


61° 28' 


26° 25' 


76 


60^ 50' 


26° 50 


77 


60° 10' 


26=- 59' 


7.S 


60° 37' 


27° .S2' 


79 


60° 52' 


2S° 58' 


So 


61° 02' 


29° 32' 


81 


6'° 44' 


27° 00' 



61°. 55' 
62° 25' 
62° 36' 
62° 36' 

62° 58' 
63'= 21' 

! 65° 03V. 
65° 02'., 
64° 58' 
64° 45' 

&4° 45' 
64° 44' 



27"^ 28' 
28° 30' 
26° 01' 

25° 30' 

25° 24' 
25° 2 1 ' 
23° 47V, 

23° 56'-- 
24° 25' 

27° 20' 
29° 06' 
31° 00' 



843 
589 

1.34 
46 

197 
486 

695 
761 
829 
780 
806 
951 
799 
653 
935 
485 
S24 
912 
472 
401 

633 
170 

76 
no 

76 

310 

568 

1236 



3°4 
3°9 



6°7 
5°5 

4°2 



4''3 
4° I 
3°6 

4°5 
4°4 
4°o 
6°j 
4°i 
3°5 



4°8 



6°9 
8=4 
4''■^ 
3°' 



92 

93 
94 

95 
96 

97 
98 

99 
100 

lOI 

102 
103 
104 

105 
106 

107 
108 
109 
no 
III 

112 

113 
114 

115 
116 
117 



64° 44' 
64° 24' j 
64^,56' 
65° 3'' 
65° 14' 
6.5° 24' j 
65° 2S' 

65° 38' 
66° 13' 
66° 23' 
66° 23' 
66° 23' 
66° 23' 
66° 23' j 
65° 34' 
65° 34' 
65° 29' 

65° 33' 
65° 30' 
65° 29' 
66° 44' 
67° 14' 
67° 57' 
69° 31' 
70° 36' 
70° 50' 
70° 05' 
69° 13' 



32° 52' 
35° 14' 
36° 19' 

30° 45' 
■,0° 39' 
29° 00' 

27° 39' 
26° 27' 

25° 53' 

14° 02' 

12° 05' 

10'' 26' 

8° 52' 

7° 25' 

7°3i' 

8° 54' 

8° 40' 

10° 28' 

12° 00' 

13° 25' 

11° 33' 

8° 48' 

6° 44' 
7" 06' 
7° 29' 
8° 29' 
8° 26' 
8° 23' 



976 
767 
204 
213 
752 
735 
450 

138 
187 

59 
537 
750 
579 
957 
762 

447 
466 

492 

97 

38 

781 

860 

1267 

1309 

773 

86 

371 
1003 



i°4 
i°46 
4°i ■ 

2°I 

I°2 
5°5 

5°9 

6°i 

o°4 
-o°7 
-o°9 
-o°6 
-i°i 
-o°8 
-0=6 

o°3 
i°i 

i°5 

o°8 
-o°9 
-i°i 
-i°o 

I°0 

o°r 
-o°4 
■i°o 



118 
119 
120 
121 
122 
123 
124 

125 
126 
127 
128 
129 
130 

131 
132 
133 
134 
'35 
136 
137 
1 38 

139 

140 
141 
142 

143 
144 



68° 27' 

67° 53' 
67° 29' 
66° 59' 
66° 42' 
66° 52' 
67° 40' 
68° o8' 
67° 19' 
66° 33' 
66° 50' 
66° 35' 
63° go' 
63° go' 

63° 00' 

63° 14' 

62° 34' 
62° 48' 
63° 01' 

63° 14' 
63° 26' 

63'' 36' 

63° 29' 
63° 22' 

63° 07' 
62° 58' 

62° 49' 



8° 20' 
10° 19' 
11° 32' 
13° II' 
14° 44' 
15° 40' 
15° 40' 
16° 02' 
15° 52' 
20° 05' 
20° 02' 

23° 47' 
20° 40' 
19° 09' 

17" 04' I 

il°24' 

10° 26' 
9° 48' 
9° II' 
8°3,' 
7° 56' 
7° 30' 
6° 57' 
6° 58' 
7° 05' 
7° 09 
7-12- 



1060 
loio 

S85 

529 

"5 
145 
495 
729 
293 
44 
194 
117 
338 
698 

747 
230 

299 
270 
256 

297 

471 
702 
780 

679 
587 
388 
276 



— i°o 

— 1°0 

— i°o 
-o°7 

i°S 

2°0 

-o°6 
— o°8 

-o°5 
5°6 
o°6 
6°5 
6°55 
4°7 
4°6 

2°2 

4°r 

o°4 
4°8 
— o°6 
-o''6 
-o°6 
--o°9 
— o°6 
— o°6 

- o°4 
i°6 



;>5;^- 



THE DANISH INGOLF-EXPEDITION. 



VOLUME V. 



8. 



MEDUSA, 

PART I. 

LEPTOMEDUS.'E. 



BY 



P. L. KRAMP. 



WITH 5 PLATES, 17 FIGURES IN THE TEXT, AND 14 MAI'S. 




COPENHAGEN. 

PRINTED BY BIANCO LUNO. 
1919. 



Introduction. 

In the present paper as also in t)ne or two more to be published later on, the Medusae from 
the northern Atlantic and adjacent waters will be dealt with. Owing to various casual circumstances 
the group of the Leptomedusae has been worked up as the first. The geographical area, dealt with 
in the said works, comprises: the Atlantic Ocean north of Lat. 50" N., tlie Davis vStrait, the western 
part of the North Sea, the Norwegian Sea, and the Polar Sea as far eastwards as the Kara Sea. The 
choice of tlie southern limit is rather gratuitous. The medusae from the British Channel are going to 
be mentioned in the "Report on the Danish Oceanographical Expeditions 1908 — 1909 to the Medi- 
terranean and adjacent Waters", dealing with the fatma of the Mediterranean and the Atlantic from 
the coast of Morocco to the British Channel. Moreover I am preparing a work on the medusae of the 
Danish waters; in the present paper, therefore, I have only included some few summary remarks on 
the medusae from that area. 

The present paper is based particularly on the collections in the Zoological Museum of the 
University of Copenhagen. Besides I have made use of a smaller collection of medusae belonging to 
the Plankton Department of the Danish Commission for Investigation of the Sea. P"or the admission 
to that collection I owe my best thanks to Professor C. H. Ostenfeld, the Director of the Plankton 
Laboratory. Moreover, during a stay in Bergen in the summer of 1916 I studied the exceedingly 
interesting material of medusae collected during the first cruise of the M. vS. "Armauer Hansen" in the 
Atlantic west of Rockall in 1913; some of the specimens were sent to me to Copenhagen for further 
investigation. With the permission of Professor A. Brink maun the results of my studies have been 
included in the present paper. I wish to express my best thanks to Professor Br in km an n for that 
permission. 

Some years ago I was commissioned to work up the Anthomedusoc and Leptomcduste from 
the "Michael Sars" North Atlantic Deep-Sea Expedition 1910. The paper was fini.shcd in 1915, and tlie 
printing was nearly accomplished, when the great fire in Bergen on January 15''' 1916 destroyed the 
matter in type; the printing has not yet been resumed, and as certain parts of the material dealt with 
in that paper are of considerable interest with regard to the problems discussed in the present work, 
I have made use of that material to such an extent as I found suitable. 

The Ingolf-Expeditiou. V. 8. ^ 



MEDUSA. 1. 



Some of the material in the Zoological Museum of Copenhagen has previously been worked 
up and mentioned in the literature. Some older material has been examined by E. Haeckel and 
mentioned in his System der Medusen. The museum possesses a Hst of that material, to which Haeckel 
himself has added the identifications of the species. The numbers in the list are refound in the labels 
of the .specimens. The said Hst is of coiLsiderable interest, as far as it has rendered it possible to cor- 
rect some of Haeckel's identifications. The medusa; from Greenland were dealt with by G. M. R. 
Levi US en in "Meduser, Ctenophorer og Hydroider fra Gronlands Vestkyst" 1892, and, later, by the 
present author in "Medusae collected by the "Tjalfe" Expedition" (1913), and "Meduser og Siphonopho- 
rer" in Conspectus Faunse Groenlandicae (1914). The last-mentioned paper includes a complete account 
of the literature relating to the medusas of the waters of Greenland. 

Besides the older material, the collections of the following expeditions have been employed in 
the present paper: 

Wm. lyundbeck, 1892 (Iceland). 

Danish "Ingolf" Expedition, 1895 and 1896 (Faeroe Islands, Iceland, and Greenland). 

Inspecting-ship "Diana", A. Ditlevsen, 1902 (Iceland). 

"Michael Sans", Ad. S. Jensen, 1902 (Norway and Iceland). 

"Michael Sans", 1903 (Norwegian Sea). 

Inspecting-ship "Beskytteren", C. V. Otterstrom 1903, K.J. Gemzoe 1904, and F. Johansen 
1905 (Iceland). 

"Thor", fisheries-investigations 1903, 1904, 1905, 1906, and 190S (British Isles, Norway, Faeroe 
Islands, Iceland). 

"Tjalfe", 1908 and 1909 (West-Greenland). 

"Armauer-Hansen", Norwegian research motorship, 1913 (West of Rockall). 

The state of preservation of the material has partly been very satisfactory (formalin), parti- 
cularly as far as the collections of the "Thor" and the "Tjalfe" are concerned. The material of the 
"Diana" is likewise generally well preserved, though it has only been treated with alcohol; the same 
testimony is partly applicable to the material from the "Beskytteren" collected by Gemzoe. The 
material from the "Ingolf Exijedition, on the other hand, is as a rule very badly preserved. Especially 
a great lot of .specimens have been spoiled owing to the usage of osmic acid or Flemmings solution. As 
a matter of fact, these substances have quite a ruinous effect on medusae, particularly so if the dis- 
solution is too concentrated and the specimens are exposed to the influence of the fluid during a too 
long space of time. Not merely the pigmentation is concealed, but the animals become intransparent 
and very much fragile, and must be handled with the utmost care not to break during the examina- 
tion. Indeed, still during the transportation in the glasses a great part of the material has been shaken 
into small fragments. Neither are the single organs better hardened for investigation by this method of 
preparation; I have tried sectioning on microtome different organs of specimens treated with Flemmings 
solution, and the tissues are by no means better preserved, rather more badly if anything, than in the 
case of animals merely preserved in common alcohol or formalin. The method of treating medusa; 
with fluids containing osmic acid seems to have been very favourite during a certain period : on account 



MEDUS.*;. I. 



of sad experiences, I take this opportunity to warn against the use of these substances for pre- 
paration of meduste. 

In the case of such species, of which no modern descriptions have been given, I have carried 
out thorough examinations of the morphology, as far as the state of preservation has rendered such 
examination possible. Also in the case of well-known species I have in some cases discovered inter- 
esting structures, hitherto unobserved. It is reall\- astonishing, how most medusse are deficientl)- 
known with regard to their morphology. It is a well-known fact, that the classification of the Lepto- 
medusse is extremely difficult. I am quite aware, that a correct understanding of the systematical 
problems must be searched for not onl\- through hatching experiments, by means of which we get 
knowledge of the connection between the hydroids and the medusae, but als(j through thorough com- 
parative-morphological investigations. As a matter of course, I cannot, in the present paper, enter into 
a discussion of the great and complicated systematical problems; my present knowledge of other forms 
of medusae than the northern species is too deficient yet for such an undertaking. Ihit it is my hope, 
that my investigations, when in course of time they are followed by others, ma\- contribute to that 
understanding which, we may hope, must be reached once in the future. 

In some cases I have discussed the historv of a species or genus in order to remove existing 
confusion or to state the correct name of the species or genus in question. 

The number of species of Leptomedusae, identified with certainty, and occurring in the north- 
atlantic area here dealt with, amounts to a little more than 25. In the material examined by me 15 
species are represented, excluding the non-identified species of Obclio. They belong to the families 
Lnndict'id(F^ Tli(nii>ia)itiiida\ Mifrocouiidcr and Eucopidcc. The family of the ^qnorid(C is not represented. 
In order to give a picture, as complete as possible, of the north-atlantic fauna of medusse, I have 
included the species of which no material has been at my disposal, but which, according to the litera- 
ture, occur within the area in question. For such species, I give a short diagnosis, mainly derived 
from A. G. Mayer, Medusce of the World, 1910, together with summary remarks on their distribution. 

The following 15 species have been examined: 

Chromatonema rubruiu Fewkes Halopsis ocellata A. Agassiz 

Laodicea undulata (Forbes & Goodsir) Tiaropsis multicirrata (M. Sars) 

Ptychogena lactea A. Agassiz Obelia nigra Browne 

Staurophora mertensii Brandt Phialidium hemisphanicum (Gronovius) 
Melicertum octocostatum (M. Sars) — islandicum nov. spec. 

Mitrocoma polydiademata (Romanes) F;utonina indicans (Romanes) 

Cosmetira pilosella Forbes Tima bairdii (Johnston) 
— megalota (Maas) 

Moreover the following species have been included (printed with Petit): 

Dipleurosoma typicum Boeck Eucheilota maculata Hartlaub 

Agastra mira Hartlaub vSaphenia gracilis (Forbes & Goodsir) 

Eucope globosa (Forbes) Eutima insignis (Keferstein) 

I* 



MEDUSA. I. 



Eutima el'ephas (Haeckel) ^qnorea forskalea Peron & Lesueur 

Octorchis gegenbauri (Haeckel) Zygpdactyla groenlandica (Peron & Lesueur) 

Eirene viridula (Peron & Lesueur) 



Family Laodiceidae Browne. 

"Leptomedusse with cordyli, commonly called sensory clubs, on the margin of the umbrella" 
(Browne 1907, p. 459). 

Browne has, no doubt correctly, ascribed the significance as a family-character to the peculiar 
organs called cordyli. Before I enter into a further discussion of these interesting organs, I will, for 
the sake of comparison, shortly call attention to the structare of another kind of marginal appendages, 
occurring in several Leptomedusse: viz. the Cirri. A cirrus is lengthened, thread-shaped, and is always 
inserted directly on the margin of the umbrella without possessing a basal bulb. The entoderm of the 
cirrus is in connection with the entoderm of the circular vessel, and it is solid (not hollow), consisting 
of a single series of cylindrical or disk-shaped entoderm-cells. The ectodermal epithelial cover is very 
delicate, consisting of flattened polygonal cells. The cirri carry nematocysts, usually in considerable 
number, and particularly towards the distal end. The distal part of the cirrus may, as a rule, be spi- 
rally curled up. 

A typical, fully developed Cord yl us is club-shaped with a thin stalk and a swollen distal 
part; it may or may not be mounted upon a small tubercle on the bell margin. In opposition to the 
cirrus, it possesses a hollow central space which, however, may be more or less obliterated ; particularly 
the lumen has often entirely disappeared in the narrow part, the lumen of the distal thick part 
thus being separated from that of the circular vessel. The entoderm consists of a single layer of large, 
usually cubical cells surrounding the central lumen. The ectoderm is fairly thin, but not so thin as 
the ectoderm of a cirrus. There are no nematocysts. This is the shape of a typical cordylus. A very 
interesting kind of cordylus, not so highly developed, has been observed by Browne in Ptychogena 
antarctica Browne (Browne 1910). The cordyli of that species, as figured by Browne (folate 2, figs. 7 — 9) do 
not possess the well-marked club-shaped appearance as in the case of the typical cord\li, but are only slightly 
more thickened distally than proximally; moreover, in some of them nematocysts were found. 

I am of opinion, that the small marginal appendages in Chrotnatoncma riibriivi indicate a 
still lower stage of development of cordyli (see Plate L figs. 2 and 3). They differ from typical 
cordyli by the possession of a cluster of nematocysts in the distal end and by the general shape which 
is cylindrical or spindle-shaped. But the ground plane, the structure of the cell-layers, is exactly as in 
a cordylus. Througli the cordyli of Ptychogena antarctica^ mentioned above, as the transitional form 
they may, I think, without difficulty be homologized with real cordyli. They may not be called cirri, 
as they have a central luniLU, and because they are short and rigid. In a nearly related species. 
Chroma tonema crythrogonon {Ptychogena erythrogonon Bigelow), further mentioned below, Bigelow 
found a few cylindrical "cirri" with nematocysts and, besides, a number of spindle-shaped "cordjli" 
without nematocysts. Excepting the lacking of nematocysts, these cordyli have exactly the same shape 
as those of Cliromatoncma rttbrui/i, and they occupy a corresponding position on the bell margin. 



MEDUSA. I. 




Thus they must undoubtedly be characterised as another transitional form, somewhat further advanced 
than the corresponding organs in Chrovioloncvta rubruiu. — In another nearly related species, Cliroviato- 
ne»ia herhvigi (Ptychogcna hertwigi Vanhoffen, see below) the same organs are, according to the figure, 
partly cylindrical, partly spindle-shaped, partly somewhat club-shaped; Vanhoffen calls them "cirri". 

Thus we find, within the Laodiceidcr, a series of transitional forms of cordyli from cylindrical 
or spindle-shaped with a distal cluster of uematocysts {Chromatonoiia rubriim) through spindle-shaped 
or slightly club-shaped with or without uematocysts, to the fully developed form: actually club-shaped 
without uematocysts. 

As different points of connection exist between the Laodicrido- and the Tiaridcr, as will pre- 
sently be demonstrated, it is a natural question, whether anything corresponding to cordyli is found 
among the latter. We will find then, that a single form of Tiaridw 
possesses certain organs, which bear a considerable likeness to the 
lowest form of cordyli, those of CIiroinatoiicDia rubrniii. The species 
in question is Tiaramia rotunda (Quoy & Gairaard). 

I deeply regret that my paper on the Anthomedusa; and 
Leptomedusse of the "Michael Sars" Expedition 1910 has not yet 
been printed, as two species of the interesting genus riamnna have pig. ■. r.art of the l.dl-margin of Tiara„„a 

, 1 ,, •.,•., . r . .1 t r ^1 rotunda ; Oiiov & Gainiard). 

been dealt with in that paper; a reference to the accounts of these ' 

species would have facilitated the following discussion on the relation between the Tiaridcc and the 
Laodiceidcr. As especially Tiaramia rotunda is of great interest in this respect, 1 have thought it 
better to make use, in this place, of my observations relating to the matter in spite of the fact, that 
they are destinated for printing in another place. 

The marginal appendages of Tiaramia rotunda (textfig. i) are very much like those 
of Chromatonema rnbnim. Between every successive pair of tentacles in Tiaramia rotunda 
there are one or two minute appendages like the cordyli of Cliroinatoncnia^ onl% they are 
never cylindrical, but always spindle-shaped, and provided with a tenon-like distal part 
greatly armoured with uematocysts (textfig. 2). The structure of the cell-layers is exactly 
as in the cord\li of Chroniatoiifina. Dwarf-tentacles of a similar shape, though more length- 
ened, are found in Bytliotiara. 

Hartlaub (1897) considered cordyli to be juvenile stages of tentacles, and he meant 
to have observed the development of cordyli into tentacles in Stauropltora nicrfensii. 
Browne has discussed this question in his paper. Revision of the ... Laodiceidcr. (1907, 
p. 458). Browne has examined a large number of specimens of Laodicea undulata (early 
and intermediate stages). He is of opinion, that transformation of cordyli into tentacles 
"t"he°clistal ^°^^ "°^ ^'^^ place normally, though such transformation may happen when the margin 
^"*^- of the bell is overcrowded with marginal organs; in such case a cordylus may stand in the 

way of a developing tentacle and may, thereby, be lifted up by the growing biilb and become situated on 
the distal end of the young tentacle; afterwards it gradually loses its rounded form and is finally absorbed. 
Browne rightly remarks: "If cordyli are the forerunners of tentacles one would naturally expect to 
see them in the earliest stage or in the very early stages; but the\' do not make their appearance 




Fig. 2. 
Dwarf-tent- 
acle of Tia- 
rautia rotuniia 
(Quoy & Gai- 
niard), with 
numerous 



MEDUSA. I. 



until the Medusa has at least trebled the original number of its tentacles". Only in very few cases 
Browne found cordyli being converted into tentacles; on the other hand, I have observed several 
cases of, the same phenomenon in Staurophora vicrtensii. Plate III fig. 7 illustrates different stages of 
cordyli being converted into tentacles in a specimen from Iceland. Fig. 7 a shows a normal cordylus 
without basal bulb; in fig. b is seen a normal cordylus mounted upon a young bulbus; figs, c — f illu- 
strate some stages of the further development into a Noung tentacle, the distal part of which is still 
distinctly club-shaped ; in stages, still further advanced, I have seen the bulbous terminal part in a 
state of absorption. ()n the other hand, I have also seen numerous young tentacles with an entirely 
pointed terminal part, tentacles which have, accordingly, never had any connection with cordyli. As a 
result of my investigations I may state, I believe, that Browne's view of this question is correct, 
though in species in which the marginal organs are very -densely crowded, it will very frequently 
happen, that cordyli are picked up by developing tentacles. 

According to Browne, the family Laodiccida: coxrv^xx?,^^ the following genera: Laodicca^ Stauro- 
pliora^ Ptychogima^ Toxorchis, Sfajirodiscns^ and Mcliccrtissa. To these we ma>- add, I believe, the genus 
Chromatonema. Among the genera mentioned by Browne, I know onh- the three first by autopsy; 
the three others I have never seen. I will, therefore, not enter into a general account of the compara- 
tive morphology of the family. But from my studies on the species, represented in tlie material at my 
disposal, I shall call attention to certain parallels to structures within the family Tiaridce, parallels 
which, after my opinion, render it probable, that the Laodiccidcc have taken their origin from that group. 

One feature, common for the Laodiccidcc (the species examined by me) and the proper Tiaridcr 
(the Ncolurridcr sensu Hartlaub) is the wide, open mouth tube, the free margin of which is more 
or less crenulated (except in the lower forms among the Tiaridcr), often complexly folded. The perra- 
dial corners of the mouth is, in most forms, more or less drawn out into four lips. Another common 
feature is the fact, that the manubrium is attached to the subumbrella along the arms of a perradial cross. 

In the TiaridiF the gonads are developed into folds or grooves in the walls of the stomach. 
Typically these grooves are arranged in the shape of four horse-shoes, the middle curves of which are 
placed interradially on the U])per (proximal) part of the manubrium, while the arms go downwards 
along both sides of the perradial edges of the stomach. From this type the arrangement may be 
further developed in a more or less complicated manner. In some of the Calycopsidcr the horse-shoe- 
shape has been obliterated, because no sexual products are developed in the interradial parts, the 
gonads thus being arranged as eight adradial rows of sacks. 

A characteristic structure in many Tiaridcr are the so-called "mesenteries", a double membrane 
connecting a greater or lesser part of the perradial edges of the stomach with the radial canals. These 
mesenteries are very differenth- developed in the different forms of Tiaridcr. In the lower forms they 
are quite absent; they are well-developed in such higher organized forms as Lcuckartiara, Catablcma, 
Neoturris, Pandea etc. If we inuigine the mesenteries so far lengthened, that they reach as far down- 
wards along the edges of the stomach as the gonads and, at the same time, just as far outwards 
along the radial canals, and if we fancy, thereafter, that they become narrowed in a dorso-ventral 
direction, the edges of the stonuich will be drawn outwards towards the radial canals and, at last, 
coincide with the latter. That is, in fact, what we find in Tiaranna rotunda and affinis (figures of these 



MEDUSA. I. 



species are given in my paper on the Anthoniedusie and Leploniedusse of the "Michael Sars"). Now 
it is not difficult to lanc\ a transition from the facts as established in these species to the type of 
gastrogenital organs found in most Laodicfida'. If the gonads disappear iu the interradial parts, we 
have, on each side of the radial canals so far as these are connected with the edges of the stomacli, 
a series of gonadial folds, forming together a continuous, folded band along the part of tlie canal 
concerned. An outward displacing (towards the bell-nuirgin) of these gonads will have the effect, that the 
proximal ends are somewhat withdrawn from the centre of the und)rella, while the distal ends, being 
removed outwards, will drag along with them the adjacent parts of the wall of the stomach, forming a 
funnel-shaped extension of the stomach along the lower side of each of the radial canals. Then we have 
the type, which is found in Ptychogoui and Laodicca (see below). The modification of this t\'pe within 
the different forms, here dealt with, will be mentioned below under the descriptions of the species. 

The emancipation of the gonads from the stomach is not so far advanced in the Laodiccidcr 
(the species here described) as in the other Iveptomedusse; this indicates a lower systematical position 
nearer to the Anthomedusa;. In Laodicca, Plychogr)ia and Stinirophora the goiuids are developed in 
folds of the lateral walls of the radial canals; iu the case of the two first mentioned genera the 
proximal parts of the gonads are frequently de\eIoped in the walls of the stomach along both sides 
of the lines (the cross-shaped figure) by which the stomach is attached to the subumbrella. In Staiiro- 
pliora the structure of the gastrogenital organs is secondarily complicated (see below). In Cliro- 
niatononii the gonads do not form continuous bands, but consist of a row of sack-shaped invaginations 
on each side of the radial canals; some of the proximal gonadial sacks are situated within the corners 
of the stomach in the dorsal walls of the latter along the arms of the cross-shaped figure. Tliese gonadial 
sacks, with their narrow, split-shaped openings, recall the gonadial sacks, arranged iu rows, in Calycopsis. 

Genus Chromatonema Fewkes. 
Chromatonema rubrum Fewkes. 

Plate I, figs. I - S, 

Chromatoiiona rubniin Fewkes 1882. Acalephae, East Coast of New F;ngland. — Hull. Mus. Conip. Zool. 

Vol. 9. No. 8, p. 305. PI. I, fig. 41. 
TJtaiiiiunitias — Mayer 1910. Medusa; of the World. \'ol. I, p. 199. 

— — Kranip 1913. Medu.sse, "Tjalfe"'-Exp. — Vidensk. iMeddel. Dansk naturh. Foren. 

Bd. 65, p. 267. 

— — Kramp 1914. Meduser og Siphonophorer. — Conspectus Faunse Groenlandica;, 

p. 419. 

'>Ptychogciui cryllirogonon Bigelow 1909. Medusae, Eastern Tropical Pacific. — Mem. Afus. Comp. Zool. 

Vol. 37, p. 150. PL 5, fig. I. PI. 38, figs. 8, 9. PI. 39, figs. 1—7. 
? — Hcrhvigi Vanh5ffen 191 1. Deutsche Tiefsee-Exped. Bd. 19, p. 220. Taf. 22, Fig. 9. Textfig. 13. 

Description. — The bell is somewhat higher than a hemisphere, the gelatinous substance 
very thick, evenly rounded at the top, gradually tapering towards the bell margin. The base of the 
manubrium is broad, quadrangular, attached to the subumbrella along the arms of a perradial cross, 



8 



MEDUSA. ' I. 



SO that there are four triangular pouches between the dorsal wall of the stomach and the subumbrella 
(see the textfig. 3, which is a copy of a drawing made from a specimen from the "Michael Sars" and 
destinated for my paper on the material of that expedition). The mouth-tube is quadrangular, very 
wide. The edge of the mouth is somewhat crenulated, and the corners are a little dilatated, forming 
four short, simple lips. The length of the manubrium is variable ; it never reaches the opening of the 
bell cavity, and in most specimens its length is less than 2/, of the depth of the bell-cavity; this 
variation may depend on the state of contraction. There are four radial canals. The proximal part 
(V2— ^/s) of each radial canal is wide and contains the gonads, the distal part is straight and narrow 
and communicates with the narrow circular vessel. The proximal part of the radial canal is funnel- 
shaped, communicating with the stomach by a perpendicular slit, somewhat broader at the top than 
at the bottom. A transverse section of the gonadial part ©f the radial canal is pear-shaped in the 

proximal part, nearly circular in the distal part. The 
line along which the gonadial part of the canal is 
attached to the subumbrella sends out a number of 
short lateral branches, so that the attachment of the 
dorsal wall of the canal has the shape of a pinnate 
figure (Plate I, fig. i and textfig. 3). Occasionally this 
figure is somewhat irregular, or it may be more or less 
zig-zag-shaped. Each of the radial canals contains two 
rows of sack-shaped gonads, attached to the dorsal wall 
of the canal in the spaces between the above-mentioned 
lateral branches of the line of attachment and hanging 
down into the cavity of the canal. The surface of a 
gonadial sack is covered with a thin entodermal epi- 
iMK. 3 ciuom.iion.ma rubrum Fewkes, seen obii(iuely theliuui (scc Plate I, figs. s, 6, 7, and 8), and each sack 

from the top. ' ' o Oi > /i /' 

has a narrow ectodermal lumen communicating with 
the bell cavity through a fissure in the dorso-lateral wall of the canal (Plate I, figs. 4, 6, and 8). In 
view of the scarcity of room, the gonads of the two sides of the canal are more or less regularly 
alternating (Plate I, figs. 5 and 6). The number of gonads varies from 10 to 16 on either side of 
the canal. The side-walls of the canal are, as a rule, tightened closely over the gonads so that the 
wall becomes faintly lobed or undulated. In the upper part of the lateral walls of the canal (outside 
the gonad.s) the entoderm consists of one layer of cubical or cylindrical cells (Plate I, figs. 5 and 7). 
In the funnel-shaped part of the canal the lower parts of the lateral walls, which are not pressed 
by the gonads, are covered with a thicker entoderm, consisting of several layers of cells (Plate I, 
fig. 7); evidently the digestion of the food takes place in this part of the radial canal. In larger speci- 
mens some of tlie proximal gonads are frequently developed in the dorsal wall of the stomach on 
either side of the cross-arms. 

There are about 20-24 solid tentacles, all of the same shape and size; the tentacular bulb is 
hollow, conical, with a heart-shaped base. There is no trace of a basal spur. The tentacles may be 
spirally coiled (Plate I, fig. 2). In a contracted state the tentacles are deeply and closely transversally 




medusa:. I. 



wrinkled. The tentacles seem to be fairly long, but owing to the state of preservation the exact length 
cannot be stated. Between every successive pair of tentacles there are two (rarely one) appendages 
which are, I think, homologous with the cordyli of the other Laodiccida-. These cordyli are cylindrical 
or somewhat spindle-shaped, provided with a cluster of neinatocysts in the distal end (Plate I, figs. 2 
and 3); they are hollow and consist of a thin ectodermal epithelium and a thick entoderm of cubical 
cells in a single layer, enclosing a central lumen, which communicates with the circular vessel. The 
cord\-li are translucent and colourless. — The velum is thin and narrow. 

The colour of the manubrium, the radial canals, the circular ves.sel, and the tentacles is brightly 
orange or brick-red; moreover the tentacular bulbs contain a brownish entodcrmal pigment-mass. The 
gonadial sacks are white. 

Dimensions. — The largest specimen, which I have seen ("Michael Sars" Stat. 84, 1910), is about 
27 mm in diameter and about 22 mm high; it has about 24 tentacles and about 16 gonads on either 
side of each of the radial canals. In the Davis-Strait the species does not seem to grow to such large 
dimensions, the largest specimen from that area, a fully mature female individual ("Tjalfe" St. 336), being 
17 mm wide, 14 mm high, with 18 tentacles, and with 13 — 14 gonads on either side of each radial 
canal. A male specimen from the Irminger Sea ("Thor" Stat. 180, 1904) shows the following dimensions: 
diameter 14 mm, height 12 mm, length of the gonadial part of the radial canals 6 nnn, breadth of the 
same 2'/2 nmi, length of the distal narrow part of the radial canals 3' ^ mm, 12 pairs of gonads on 
each radial canal, number of tentacles not stated. 

Distribution. — VVidel)' distributed in the deep parts of the northern Atlantic north of abotit 
40° N. Towards the North the distribution is limited by the submarine ridge Scotland — Facroe Is- 
lands— Iceland— Greenland— Baffin Land. The northernmost locality is: Lat. 65° N., Long. 54° W. (Mol- 
ler), southernmost: Lat. 39° 52' N., Long. 69° 45' W., westernmost: LaL 39° 57' N., Long. 70° 15' W., eastern- 
most: Lat. 61° 15' N., Long. 9° 35' W. 

Batliy metrical Distribution. — The species occurs almost exclusively in the deeper strata. 
Most specimens have been caught with instruments for pelagical fishing with 1000— 3000 m wire out, 
i. e. about 600 — 2000 m below the surface. During the Atlantic expedition of the "IMichael Sar.s" in 
1910, however, a specimen was taken by a haul with 100 m wire (stat. 81, Lat. 48° 02' N., Long. 39° 
55' W.), and in one case the species has even been taken with a hand-m-t at the surface, viz. off the 
west-coast of Greenland by H. P. C. M oiler (.see below). 

The first published description and figure of this medusa were given by Fewkes (1882). But 
the species has been figured and described many years before, though that figure as well as the de- 
scription seems to have disappeared. 

In the Zoological Museum of the University of Copenhagen I ha\e fmind a specimen, collected 
by H. P. C. Mo Her off the west-coast of Greenland. Though only slight traces of the gastrogeuital 
organs are left, these slight traces in connection with the tentacles, which are fairly well preserved, 
partly expanded, and the entire shape of the medusa, with its very thick gelatinous substance, put it 
beyond doubt that the specimen must be referred to the species Chroinatoticma rubniin. The specimen 
was in a glass-tube with a label of the content shown on p. 10. The Zoological Museum possesses a large 
number of notes and drawings made by H. P. C. Moller, who was inspector in Cheenland for .some 

The Ingolf-Expedition. \'. S. 



jQ MEDUSA. I. 



years about 1840. On his journeys he made considerable zoological collections, particularly of molluscs, 

and put down his observations in his journals. While looking through these old papers I succeeded in 

finding ^^^^Oceania cardinalis'^ mentioned in a journal from 1843; among some other notes from June 

13th is the following: "June 13th, off Napparsok. Last night the weather was completely calm, and 

with the hand-net several things were fished to me at a distance from the land of about 40 miles, to 

wit: a remarkably pretty small Acaleph, which I have not seen before, and which I have drawn and 

described this afternoon (provisionally I will call it Occatiia cardinalis) ..."' 
Oceania . .... 

,• ,■ Now was the question: where are that drawing and description? With the 

13. Juni. Sukkertopp. exception of the date and the locality, the marks on the label could give me 

Sp. t. Journ. 76. j-jQ information. At first I could not even understand the significance of these 

III fio-. A. 

" marks, until I found, that they ara partly due to erroneous copying: "Sp. F 

Journal" ought to be "Sp. S. Journal", i. e. "Spanske So Journal" (M oiler 
calls the Atlantic with the name of Spanske S0 (Spanish Sea), and one of his journals bears that title); 
and "76" is a mistake for "Tb", i. e. "Tabula". And when I found "Spanske So Journal Tab. Ill, fig. A" 
I saw a drawing of some crustacean. It is evident, however, from the journal of 1843 that a descrip- 
tion and drawing must have been made, but in spite of keen searching I have not found them. It is 
probable, however, that they have disappeared very soon, because the species is not included in 
M or ell's list of the Acalephs of Greenland, 1857. The species mentioned in that list have been derived 
"partly from descriptions in Fabric! i Fauna Groenlandica, partly from various posthumous drawings 
of H. P. C. M oiler" (loc. cit. p. 98). 

This find is of considerable interest, because it is the only time the species has been found at 
the surface and because the said locality is the northernmost place, where the species has hitherto 
been found. Napparsok is on the west-coast of Greenland a little south of Sukkertoppen. According to 
the quoted journal of M oiler the position of the locality must be: Lat. 65° N., Long. 5^^° W. 

The description of Fewkes is based upon 7 specimens, found during the investigations of the 
U. S. Fish Commission off the southern coast of New England in 1881, stat. 936 and 954. These sta- 
tions are near the northern limit of the Gulf-Stream. The depth in which the specimens were 
taken, is not seen from the available data. P'ewkes's description and figure are very deficient, prob- 
ably owing to the bad state of preservation of the specimens. The gonads are said to occupy the 
pro.ximal one-third of the radial canals, and Fewkes .speaks about large white eggs (which evidently 
mean the white gonadial sacks), which, according to the figure, are placed irregularly within the 
"gonad.s". In ever\' other respect the specimens, examined by me, agree so well with the description 
and figure given by Fewkes that I have not the sHghtest doubt, but that they belong to the same 
species. As to the systematical position of the medusa, Fewkes .states that it is "apparently allied to 
Staurophord!\ but that the determiuation of its exact position is difficult; he will, therefore, provisionally 
call it with the name of Chroiiiattiiiciini y/i/>ni///, till its position can be fixed. 

Mayer (1910) quotes the description of Fewkes and places the species within the genus 
T/ia7tniantias. 

' "Den 13. Juni, paa Hoideu af Napparsok. Iiiat var (let aldele.s stille og der blev da nied Ketzeren fanget adskilligt 
til iiiig i en Afstand fra Landet af en halv Snees Mile, neuilig en udniierket stuuk lille Acaleph, soui jeg ikke for har seet, og 
soni jeg i Eftermiddag har tegnet og beskrevet (jeg vil foreliibig kalde den Oceania cardinalis) . . .". 



MEDUSA. I. J J 



During the cruise of tlie "Tjalfe" to the west-coast of Greenland in 1909 seven mednsse were 
found in deep water in the Davis vStrait; tliL\ were identified by me as belonging to the species here 
dealt with and shortly mentioned with the name ])roposed by Mayer, Thaiimnntias rubruni (Kramp 
1913I, and with the same name I included the species in my list of the medusae of Greenland in 
"Conspectus Faunae Groenlandicte" (Kramp 1914). A more detailed description of this interesting 
medusa was postponed, till I had examined the specimens, taken on the ''Michael Sars" North-Atlan- 
tic Deep-Sea Expedition 1910; these specimens had already arrived to me in the Zoological Museum. 
As my paper on the "Michael Sars" medusa.' has not yet been ])rinted (cf. p. 1), I have given the de- 
scription in exteuso in the present paper and, moreover, added several new observations, made on 
the material from the "Tjalfe" and on two specimens collected during the cruise of the "Thor" 
in 1904. During the cruise of the Norwegian motor-schooner 'Armauer Hansen" in the Atlantic 
in 1913 5 specimens of the same species were found, which I had the oiijiortvuiity of examining in 
Bergen in 1916. 

Altogether 34 specimens of this medusa are known up to now. 27 of these sj^ecimens have 
been at my disposal for examination. 

In the following complete list of the localities, where the species has been found hitherto, the 
localities are arranged in the following manner: i. the Greenland occurrences from the North towards 
the South, 2. the Atlantic occurrences from the West towards the East. 

Eat. 65° N., Eong. 54° W., about 40 miles west of Napparsok on the we.st-coast of Greenland. 
June 13th 1843. Surface. H. P. C. Moller. — i specimen. 

Eat. 64°o6' N., Eong. 55°i8' W., Davis vStrait. May 8th 1909. Depth 1046 — 1100 m. Ringtrawl, 
1200 m wire. "Tjalfe" stat. 336. — 4 specimens, 11 — 17 mm wide with 15 — 18 tentacles (for further 
details, see Kramp 1913 p. 267). 

Eat. 63°i8' N.. Eong. 54°55' W., Davis Strait. Alay 7th 1909. Depht 1300 m. Ringtrawl, 1530 m wire. 
"Tjalfe" stat. 333. — 3 specimens, 9 — 15 umi wide. 

Eat. 39°57' N., Eong. 70°i5' W., 91 miles S '/^ E of Martha's Vineyard, New England. August 
23rd 1881. Depth 1174 m (642 fms.). U.S. Fish Comm. stat. 954. (Fewkes 1882). — 2 specimens. 

Eat. 39°52' N., Eong. 69°45' W., io4'/, miles S. by E. '/, E. of Martha's Vineyard, New England. 
August 4th 1881. Depth 1289 m (705 fms.). U.S. Fi.sh Comm. stat. 936. (Fewkes 1882). — 5 specimen.s. 

Eat. 42°59' N., Eong. 5i°i5' W., southern edge of the Newfoundland Bank. June 30th 1910. 
Depth iioo m. Ringtrawl, 700 m wire. "Michael Sar.s" stat. 70. — i specimen, diameter 23 mm. 

Eat. 47°34' N., Eong. 43°!!' W., eastern slope of the Newfoundland Bank. July nth 1910. Depth 
about 2000 m. "Michael Sars" stat. 80. — a. Young-fish trawl, 1000 m wire. 2 .specimens. — b. Ring- 
trawl, 1500 m wire. 2 specimens. 

Eat. 48°o2'N, Eong. 39=55' W. July 12th 1910. "Michael Sars" stat. 81. — a. Ringtrawl. room 
wire. I specimen. — b. Young-fish trawl, 1000 m wire, i specimen, diameter about 17 mm, about 20 tent- 
acles. — c. Young-fish trawl, 2000 m wire, i specimen, diameter 16 mm. 

Eat. 48°24' N., Eong. 36°53' W. Juli 13th 1910. "Michael Sars" stat. 82. — a. Young-fish trawl, 
1000 m wire, i specimen, diam. 21 mm. — b. Young-fish trawl, 2000 m wire, i specimen. 



12 MEDUSA. I. 



Lat. 48°04' N., Long. 32°25' W. July 15th 1910. "Michael Sars" stat. 84. — a. Ringtrawl, 2500 m 
wire. I .specimen, diam. 26 mm. — b. Yonng-fish trawl, 3000 m wire, i specimen, diam. about 27 mm, 
about 24 tentacle.s. 

Lat. 54°5i' N., Long. 28°i5' W. July 17th— i8th 1913. 1000 m wire. "Armauer Hansen" stat. 9. — 
3 specimens: i. Diam. about 17 mm, three-rayed. 2. Diam. ig mm, height 15 mm, 20 tentacle.s. 3. A large, 
defect specimen. 

Lat. 54°05' N., Long. 26''o8' W. July 15th 1913. 1000 m wire. "Armauer Hansen" stat. 7. — 2 
specimens, diam. 18 — 22 mm. 

Lat. 6i°34' N., Long. i9°05' W., Irminger Sea. July loth 1904. Depth 2160 m. Young-fLsh trawl, 
probably 1800 m wire. "Thor" stat. 180 (04). — i specimen, diam. 14 mm. 

Lat. 6i°i5' N., Long. 9°35' W., north-west of the Faroe Bank. May 22nd 1904. Depth 872—970 m. 
Young-fish trawl, 1000 — 1700 m wire. "Thor" stat. 99(04). — i specimen, diam. 15 mm, about 16 tentacles. 

The specimens from the "Michael Sars" and the "Armauer Hansen" are in Bergens Museum, 
the specimens from the "Thor" and the "Tjalfe" are in the Zoological Museum of Copenhagen. 

Among the 5 specimens from the "Armauer Hansen" two are abnormally developed. One 
specimen from stat. 9 has only three radial canals; a specimen from stat. 7 shows tlie following features: 
It is a female individual, 22 mm in diameter. One of the four radial canals bifurcates at the point of issue 
from the stomach, forming two complete gonadial systems; at the distal ends of these the two branches 
of the canal unite once more, so that the distal part of the canal, free of gonads, is simple. Two others 
of the canals, otherwise normally shaped, converge verv much in their distal };arts and reach the 
circular vessel so near each other, that only one tentacle finds room between them. 

The distribution of Clironiatoiona rubruni (see Chart I) is true oceanic and extends over the 
deep basins of the North-Atlantic on both sides of the submarine ridge which divides the Atlantic 
into a western and an eastern basin. The distribution of the si^ecies in the western basin extends 
northwards to the southern slope of the submarine ridge between Greenland and Baffin Land. In the 
eastern basin the north-limit of the distribution is the Wyville Thomson ridge. With two exceptions, 
viz. MoUer 1843 (ss"^ below) and "Thor" vStat. 99 (depth 872— 970 m), all of the localities are from 
outside the 1000 m line. The specimens mentioned by Fewkes were taken on the .slope outside the 
coast of New England south of Cape Cod. The "Michael Sars" found the species on the southern slope 
of the Newfoundland Bank (depth iioo m) and east of the same bank (depths more than 2000 m). The 
specimens brought home by the "Armauer Hansen" were found near the 3000 m line, and b)- the 
"Thor" the species was found outside the 2000 m line south of Iceland (stat. 180), and near the 1000 m 
line north-west of the Faroe Bank (stat. 99). The "Tjalfe" found it between 1046 and 1300 m in the 
Davis Strait. 

The .species has mostly been found far below the surface of the ocean, between 600 and 2000 m, 
i. e. in the true oceanic water. Thus in the (Uilf-Stream area the species does not, as a rule, rise to 
the water-masses of that current, but keeps itself in the deeper and colder water layers. The "Michael 
Sars" stat. 70 on the southern edge of the Newfoundland Bank is north of the northern limit of the 
Gulf-Stream; here a .specimen was caught about 400 m below the surface. 



MEDUSA. I. 



13 



Though the species lias, mainly, a batlupelagical occurrence, it may, however, occasionally rise 
to the upper water layers. On "Michael Sars" stat. 81 a specimen was fished by the ringtrawl with 
100 m wire in water of a fairly high temperature (about 13° C). 

More astonishing is the find, made by Mollcr, off the west coast of Greenland (see above, 
p. 9). It is a well-known fact that oceanic deep-sea organisms are occasionally carried towards the 
■west coast of Norway and found there near the shore and in the upper water layers. vSimilar pheno- 




Chart I. Occurrence of C/iramatoncma rubrum Fewkes in the northern Atlantic. 



mena have been observed on the west coast of Greenland, and this nia\- account for the appearance 
of this oceanic deep-sea medusa comparatively near the coast and swinnning at the surface of the water. 

The hydroid stage is unknown, and no young stage of the medusa has been observed; it is 
impossible, therefore, to state, or even to guess, anything with regard to the development of the .species. 

Related Species. — Bigelow (1909) has described a similar medusa from the eastern tropi- 
cal Pacific (the Humbolt-Current off the coast of Peru, in intermediate strata). He called \\. Ptychogena 
erythrogonofi. Bigelow possessed a series of specimens in different stages of growth, the largest being 
38 mm in diameter by 25 mm high. The general appearance of the species bears a striking resem- 



J. MEDUSA. I. 



blaiice to that of Clirotnatoiicvia rubniiii. The largest .specimens have as much as about 64 tentacles; 
the tentacle bulbs have exactly the same shape as in C/iyoii/afoiifiiia riibnim (op. cit. Plate 39, fig. 5). 
According to the description Bige low's species possesses both cirri and cordyli. Only a few cirri 
were present in his specimens; they are cylindrical and provided with a cluster of nematocysts in the 
distal end. The cordyli are spindle-shaped and carr>- no nematocysts. One or two cordyli are present 
between every two successive tentacles. As mentioned above the cordyli of Chromntoitona riihntiii may 
be cylindrical or more or less spindle-shaped, in both cases provided with nematocv-sts, and they are 
situated in a manner very similar to the arrangement of the cordyli described by Bige low. The 
"cordyli" of ^'•PtycJiogcna cryflirogonoiP^ are undoubtedly homologous with the cordyli of Chro))iato>iema 
rubruni; as to the homologies of the "cirri" of the former I am not quite sure; the drawing of a single 
"cirru.s" (Plate 38, fig. 9) recalls the cylindrical form of cordvli in Chroviatone?)ia rubriivi, only a little 
more lengthened and somewhat more heavily armoured with nematocysts; in fig. 5 of Plate 39, however, 
the name of "cirrus" is attached to an organ which is undoubtedly a young tentacle. 

As in Chroiiiatoncuia ntbnciii, the base of the manubrium of ^'Plychogena crythrogonoiC^ is qua- 
drate and attached to the subumbrella along the arms of a perradial cross. The mouth-tube is said to 
be barrel-shaped, while I have described it as being quadrangular in C/iroii/afoini/ia rnbrum\ but it is 
very likely, that the mouth-tube of the last-named species may attain a circular outline when fully 
expanded; such is the case in several other species, in which the stomach is qiradrate when not ex- 
panded. The shape of the radial canals and the gonads of ^'Ptychogena erythrogono)i" is exactly as in 
Chromatoncma rubriiiii^ the radial canals having "developed a series of short lateral diverticula along 
the narrow lines by which they are attached to the subumbrella (Plate 39, fig. 2). The main bodies of 
the canal.s, however, are so stout that they extend out as far as the ends of these short branches. The 
gonads develop in the spaces between the diverticula, and are confined to the aboral surfaces of the 
canals close to the subumbrella . . ." (op. cit. p. 151). The distal narrow part of the radial canal is 
shorter in ^'•Ptycliogcna crythrogoiioir than in Chromato)irina ruhriiin. — The colour seems to be the 
same in both species. — The two .species are undoubtedly nearly related and must be referred to the 
same genus. In fact, I can see no other noticeable differences than the want of nematocysts in the 
cordyli of the Pacific species, and the size, Chroviatoncma ntbrum reaching maturity when about 20— 
24 mm in diameter with about 20—24 tentacles, whereas Chrornatnncma crythrogo77on grows to a larger 
size and may possess 64 tentacles when fully developed. 

Another .similar form is described by Van h of fen (191 1) as Ptychogena Hcrtnugi, found in the 
Indian Ocean by the German deep-sea expedition. Vanhoffen describes his species as very like 
Ptychogaia crythrogouoii Bigelow, but still larger, 50 mm in diameter, yet with a smaller number of 
tentacles, viz. 20. It has no cord>li but 5 cirri between each successive pair of tentacles. The "cirri", 
as .sliowu in the figure in the text, seem to be partly cylindrical, partly somewhat club-shaped, partly 
spindle-sliapcd. According to the coloured figure (Taf. XXII, Fig. 9) the gonads reach only to the 
middle of the radial canals. Al.so this species is undoubtedly nearly related to Cliromntouoiia riibrum 
Fewkes and belongs to the same genus. 

Further investigations will show whether the three species mentioned are distinct or only local 
varieties of one and the same species, viz. Chromaionenia mbrum Fewkes. 



MEDUS.?;. I. 



15 



Table I. Synoptic Table of the Species of Chroma tonciiia 



Diameter of fuU-growu medusa 

Number of tentacles in full-grown medusa 

Number of cordyli between each successive pair of tentacles 

Occurrence ' 



C. rubrum C. erythrogonon ' C. hertwigi 
I"ewkcs Bigelow 1 VaiiluiffLii 



24— 27 mm I 38 mm 

ca. 24 1 ca. 64 

2 (I) I (2) 

Northern At- Eastern tropical 
lantic Ocean Pacific 



50 mm 
20 



Indian Ocean 



Systematical Position. — The structure of C/iroiiiatoiiciii(i presents, in several regards, a 
considerable resemblance lo the members of the family Laodiceidce previously known, particularly to 
the genera Laodicra and Plycltogcna. In all of the three genera the manubrium has the same shape: 
the square stomach, the broad base of which is attached to the subnnibrella along the arms of a 
perradial cross; the short, wide mouth-tube, and the folded mouth-edge, in the four corners of which 
lips are just indicated. Common for tlie three genera is, moreover, the structure of the four radial 
canals; the proximal part of each of the canals contains the gonads; the ventral part of this gonadial 
part is funnel-shaped and is the proper digestive part of the canal. In Cliromato7ieiim as in PtycJwgrna 
the dorsal line of attachment of the radial canal to the subumbrella is pinnate, and in older individu- 
als of all of the three genera the proximal part of the gonads may be developed within the corners 
of the stomach in the dorsal wall of the latter on both sides of the arms of the jjerradial cros.s. But 
with regard to the structure of the gonads Clironiafo)ic)no presents a considerable difference, not only 
from Ptychogena and Laodicea, but from all other Leptomedusse. As described above each of the radial 
canals in Chromatonema carries two rows of sack-shaped gonads, complete!}- independent of one another. 
In all other Leptomedusa; each radial canal bears either two lateral gonads, forming two continuous 
masses in the ectoderm of a certain part of the lateral walls of the canal, or only one gonad com- 
pletely surrounding a shorter or longer part of the canal. (A special case is the gonads of certain 
species of Eiitiina, being transversally divided into two separated pairs 
of gonads, one pair on the subumbrella, one pair on the stomachal peduncle). 
In some forms the gonadial bands are straight and linear, in others they 
are more or less undulated or folded. In Laodicca the lateral walls of the 
gonadial parts of the radial canals have a number of short lateral pouches; 
in Ptycltogcnn these pouches are niucli more highly developed and lui\e 
attained the shape of vertical lamella;, the dorsal edges of which are atta- 
ched to the subumbrella; but still there is only one gonad on each .side of 

the canal; there is onh' one gonadial band, but it is highlv folded. In 

I-"ijr 4. Diagrams, showing the 
Stajirophora the gonads have a similar structure, but the folding is still structure of the gonads of 

Chromatotifina (a) and Ptycho- 

more complicated. 

The structure of the gonads of a C/irouiafoiirma and a Ptycliogrna 
may be illustrated by a diagrammatic figure as the textfig. 4. This diagram corresponds to that by 
which Hartlaub (1914, p. 347) illustrates the typical folding of the gonads in the two groups of 
TiaridcE, viz. the Calycopsidcc and the NeotiirridcF. It is not difficult to refer the tw^o types to a common 




Chroinatoneina {a) and Ptyc 
gum {0). — /inner side, outer 
side. 



j6 medusa. I. 



ground-plane, and though the peculiar structure of the gonads of Clirotnatonema places that genus in 
opposition to the other members of the family Laodiccidcr^ this structure does not contradict the 
supposition of a generic relationship. 

The parallel between the structure of the gonads of ChroviatoncDia and of the Tiaridw men- 
tioned above is hardly a casual one. There is, in fact, a striking resemblance between the gonads of 
Chromatonoiia and the eight adradial rows of gonadial sacks, communicating with the bell-cavity 
through transversal fissures in the outer surface of the manubrium in a Calycopsis (see the figure of 
Bigelow, copied by Hartlanb, 1913, P- 347. and the transversal section, Vanhoffen, 1911, Textfig. 
loa, p. 216, copied by Hartlaub, 1913, jj. 348. Compare also Hartlaub's Fig. 238, (1913, P- 287) of 
the gonads of a young Lcnckartiara ocfoiia, seen from the inner side of the manubrium). The impor- 
tance of the resemblances between the gonads of the Tiaridcr and the gonads of Chroma ioncma and 
the other Laodiceidcr is mentioned above in the introduction to the family Laodiceidce (pp. 6 — 7). The 
marginal appendages of Cliromatoneina and their relations to the corresponding organs of the other 
Laodiccida: and the Tiaridcc were also mentioned above. 

Thus my considerations with regard to the systematical position of C/iroiiiafoi/ei>ia lead to the 
result, that it belongs to the family Laodicridcr, among which it takes a low position, jsresenting several 
features pointing to the connection with the Tiarid(r. Its position among the Laodiccida- is, however, 
not only a low, but also in certain regards a singular position, particularly owing to the peculiar 
structure of the gonads, and it seems probable that the genus has arisen from some other group of 
Tiaridcc than the predecessors of the other members of the Laodiceidcr. 

Genus Laodicea Lesson. 
Laodicea undulata (Forbes & Goodsir). 

I'lati: II, figs, 1—8. 
1 Medusa cruciata Forskal 1775. Descriptiones Animalium, p. no. — 1776. Icoues rerum naturalium. 

Tab. 5, Fig. A. 
Tliai(nia)iiias iiiidiilula Forbes and Goodsir 1851. — Transact, Royal Soc. Edinb. Vol. XX, p, 313. 

Plate 10, fig, 7, 
— mcditerranca Gegenbauer 1856. — Zeitschr. wiss. Zool. Bd, \'III, p, 237. Taf. 8, Fig. 1—3, 

Laodicea calcarata A. Agassiz, in L. Agassiz 1862. Contrib. Nat. Hist. U. S. Vol, 4, p. 350. 
Laodice ulothrix Haeckel 1879. System d. Medusen, p. 133. Taf. 8, Fig. 5 — 7, 
Laodicea marama A. Agassiz and Mayer 1899. Acalephs, Fiji Islands. — P.ull. Mus. Comp. Zool. Vol. 

XXXII, p. 162. Plate 3, figs. 7—8. 
Laodice indica Browne 1905 b. — Pearl Oyster Fisheries, vSuppl. Rep. 27, p. 136. Plate I, fig. 5; Plate IV, 
figs. 7— II. 

— — Browne 1907. Revisiou of the . , . Laodiceidte. — Ann. Mag. Nat, Hist. Ser. 7, Vol. XX, 

p. 460. 
Laodicea cruciata Mayer 1910. Medusic of the World, p. 201. Textfigs. 104—105. Plate 21, figs. 4 and 5; 
Plate 22, fig.s. 2—6; Plate 23, figs. 1—3. 

— Bigelowi Neppi et Stiasny 191 1. Zool, Anz, Bd, 38, p. 396. 



MEDUSA. I. 



1 Laodicea fijiana A. Agassiz and Mayer 1899. — Bull. Mus. Coinp. Zool. Vol.32, p. 163. Plate 3, figs. 9 10. 

1 Laodice — van indica Maas 1905. Craspedote Mcdusen d. Siboga-Exped. — Siboga-Exped., 

Monogr. X, p. 25. Taf. 2, Fig. 14—15; Taf. 5, Fig. 32-35. 
? — Maasii Browne 1907. Revision of tlie . . . L,aodiceid£c. — Ann. Mag. Nat. Hist. Ser. 7. Vol. 

XX, p. 466. 
? — iinuisi Vanhoffen 191 1. — Deutsche Tiefsee-Exped. Bd. 19, p. 221. 

Description: The bell somewhat flatter than a hemisphere. The gelatinous substance not 
very thick, about 2—3 mm at the apical point, evenly diminishing in thickness towards the bell- 
margin. The diameter of the bell is usually about 25 mm, but it may amount to 37 mm. The stomach 
is quadrate, spacious; its diameter is about one-fourth of the diameter of the bell. The stomach is 
fairly short, and the walls are rather thin. The mouth edge is folded in large folds; lips are just 
indicated, the four corners of the mouth being a little dilatat'ed. The mouth-edge bends outwards, 
forming a narrow, outturned edge. The dorsal wall of the stomach is attached to the subumbrella 
along the arms of a perradial cross, four flat, triangular pouches being formed between the dorsal wall 
of the stomach and the subumbrella. The figure of attachment i.s, however, in .several ca.ses not exactly 
cross-shaped, but the four cross-arms meet somewhat obliquely (see Plate II, fig. 2). When seen from 
the mouth the cross has the appearance of four concurrent grooves. Near the centre of the stomach 
these grooves are open, but before they reach the corners of the stomach each of the grooves becomes 
transformed into a closed canal, on account of the sides of the groove being developed into two folds 
meeting each other from l)oth sides, frequenth' after a wavy line (Plate II, figs. 2 and 3). 

There are four radial canals, attached to the subumbrella b\' a very narrow line, straight or 
slightly sinuous. The distal part (2 — 4 mm) of each of the canals is free of gonads and communicates 
with the narrow circular vessel. The main part of the canal is occupied by the gonads, forming two 
lateral bands, provided with a number of short, rounded lateral extensions, usualh' 6 — 8 on each side 
of each of the canals. In fully de\^eloped individuals the breadth of the gonadial part of a radial canal 
is about 3 mm. The gonads commence, in well-developed specimens, at a considerable distance within 
the corners of the stomach, at the same point where the four dorsal grooves turn into closed canals 
(see Plate II, fig. 2). The gonads occupy only the dorsal part of the lateral walls of the canal; below 
the gonadial part there is a thin-walled part, which opens like a funnel into the corner of the stomach ; 
this funnel-shaped part is separated from the space between the gonads by two lateral longitudinal 
folds, continuations of the folds along the dorsal grooves in the stomach, mentioned above (Plate II, 
figs. 2 and 3). At the distal end of the gonads the separation between the dorsal (gonadial) and the 
ventral (funnel-shaped) part is, as a rule, not complete. Microtome-sections demonstrate, that the ento- 
derm is quite thin in the gonadial part of the wall, but much more highly developed in the walls of 
the funnel-shaped part; we must suppose, therefore, that the digestion of the food takes place in the latter. 

The bell-margin carries a very large number of tentacles; in well-.sized specimens the number 
amounts to about 600. In well-preserved specimens the tentacles are, usually, as long as the bell- 
radius; the distal end is spirally coiled. The tentacles are hollow. Tentacular bulbs are but .slightly 
indicated, the proximal part of the tentacles being a little inflated. The ectoderm of the basal bulb is 

Tlic Ingolf-Expedilioii. V. 8. 3 



l8 MEDUSA. I. 



thin except on the adaxial side, where it is somewhat thickened (Plate II, figs. 5 and 6). The young 
tentacle issues from the proper margin of the bell and possesses an abaxial entodernial spur-like process, 
imbedded in the gelatinous substance on the exuinbrellular side of the bell-margin (Plate II, fig. 5). 
During the continuous growth the adaxial side of the basal part of the tentacle grows faster than the 
outer side, and thereby the point of issue of the tentacle is gradually removed from the bell-margin upwards 
on the outer side of the bell ; older tentacles, therefore, issue from the exumbrella at some distance 
above the bell-margin (Plate II, figs. 6 and 8). On account of this removal the abaxial part of the 
tentacular base, which is pushed upwards on the outer side of the umbrella, invests the spur-like 
process, which at last entirely disappears (Plate II, fig. 6). Accordingly, a "spur" is only present on the 
young tentacles. The fully developed tentacle turns abruptly outwards and downwards, immediately 
after leaving the wall of the umbrella. The central canal in the tentacle has not the same width 
everywhere, but expands and narrows at different points (Plate II, fig. 8); the greatest width is a little 
outside the point of issue of the tentacle. The course of the canal is approximately central, except in the 
basal part, where it passes the sharp bend very close to the adaxial side (Plate II, fig. 6). Within the 
imbedded part of the tentacular base the canal is very narrow and opens in the circular vessel. In 
young individuals, in which the tentacles are not so densely crowded on the bell-margin, the basal 
bulbs are fairly broad, all the tentacles issue from the margin itself, and spurs are onl}' just be- 
ginning to develop. 

A small, dark, .sharply defined ocellus is found on the adaxial side of the base of some of the 
tentacles. The number of ocelli is subject to much variation; as a rule ocelli are found on every 3rd — 
5th of the tentacles, but they may be foimd on every 2nd tentacle, rarely on two successive tentacles. 

Typical cordyli are situated between the tentacles (Plate II, figs. 5, 6, and 8). The cordyli issue 
from the bell-margin close by the base of the velum; they are very small, hardly longer than the 
proximal breadth of a fully-developed tentacle; they have, as a rule, a fairly thick distal part and a 
very thin peduncle. In some of the cordyli the inner lumen is fairl>' large, in others it is very narrow or 
nearly obliterated, being just visible as a fine streak; this variation stands in no relation to the size 
of the cordylus. Some of the cord>li may be mounted upon fairly large bulbi; in such cases their 
basal part is turning inwards (adaxially). The number of cordyli is variable and may be a little larger 
or a little smaller than the number of tentacles. This seems to depend on the stage of development 
of the individual; in full-grown specimens the number of cordyli is, probably, always the same as the 
number of tentacles. 

The bell-margin also bears fine cirri, which may be spiral!)- coiled, and which are greath' armoured 
with nematocysts in their distal part. According to Mayer the cirri are "usually somewhat less 
numerous than the tentacles"; in preserved material, as a rule, only a small number of cirri are left; 
the material, examined by me, therefore, gives no available information of their number. In badly 
preserved specimens I have, in fact, been unable to find any cirri at all. 

The velum is fairly well-developed; in full-grown specimens it is about 3 mm wide. 

The colour is subject to much variation. The manubrium, the gonads, and the tentacular bulbs may 
be reddish or greenish or nearly colourless. Most of the specimens, examined by me, are reddish, provided 
that the colour is preserved. In an individual from the "Thor" stat. 72 (1905), the gonads are pale green. 



MEDUSA. I. iQ 



The material contains a number of yonng individuals, viz. from the "Michael Sars", south of 
the Myrdalsjokel, Iceland, i^/s 1903; from the "Thor" stat. 45(08), Iceland; from two localities near the 
Hebrides, "Thor" stat. 8(08) and 11 (08]; and from the Horns Rev light-vessel, west of Jutland, ^5/,^ 1912. 
The smallest specimen is 5 mm wide. These young individuals show that the margins of the dorsal 
grooves in the wall of the stomach begin at an earl\- stage to develop into folds which meet and 
transform a part of the groove into a closed canal; further that the gonads first appear near the 
corners of the stomach and, from these points, develop parth' in a centripetal direction towards the 
centre of the stomach, which is, however, never reached, partly in an outward direction towards the 
circular vessel, which is, likewise, never reached. At an earl)- stage the transversal folds of the gonads 
begin to form; in a specimen, 7 mm wide, each of the gonads has 2 — 3 pairs of transversal folds; in 
an individual, 9 mm wide, there are 6 pairs of folds on each of the gonad.s. When the diameter of the 
bell is about 20 mm, the gonads are somewhat far developed, particularly the female gonads, which 
already now contain very conspicuous eggs. 

The structure, mentioned above: that the ventral, funnel-shaped part of the radial canal is 
separated from the dorsal gonadial part by two lateral longitudinal folds, does not seem to have been 
observed by previous authors. In this part of the gastro-genital S3steni there is established a very 
interesting differentiation into two parts with different functions. The ventral, funnel-shaped part 
receives and dissolves the organisms, which serve as food for the medusa; they are however prevented 
from penetrating into the dorsal part between the gonads on account of the longitudinal folds; the 
dissolved nutritive matter, on the other hand, may pass between the folds into the dorsal part. Prob- 
ably a part of the food is also digested in the stomach and may, by means of the ciliary motion in 
the dorsal grooves, be carried into the dorsal part of the radial canal; this part, accordingly, has two 
functions: to carry the gonads in its lateral walls, and to transport the nutritive substances into the 
peripheral parts of the canal s)stem. 

From what is said above with regard to the development of the gonads, it will be understood, 
that the length of the distal part of the radial canals free of gonads in proportion to the radius of 
the bell is considerably larger in young specimens than it is in full-grown individuals. In specimens, 
about 10 mm wide, the gonads reach to the middle of the radial canals. In full-grown individuals the 
length of the gonads is very variable. In a specimen, 28 mm wide, from Iceland ("Thor" stat. 241 (09)) 
the distance from the distal end of the gonads to the circular vessel is 2 mm; in another specimen, 
30 mm wide ("Thor" stat. Da. 13 (04)), the length of the gonads is 9.5 mm; they commence 1.5 mm from 
the centre of the stomach and terminate about 4 mm from the circular vessel; in a specimen, 35 mm 
wide ("Thor" stat. 180(04)), the length of the gonads is about 15 mm; they commence very near the 
centre of the stomach and terminate 2.5 mm from the circular vessel. 

The number of tentacles is considerably larger than is usually stated in the literature. It is 
possible that the locality plays a part in this respect. All the specimens examined by me have been 
found in the waters around Scotland, the Faeroe Islands, Iceland, Norway, and Denmark. The smallest 
individual is from the Horns Rev light-vessel, ^3/,, 1912; it is 5 mm wide and has about 48 tentacles, 
placed at some distance from each other; in accordance herewith the basal bulbs are comparatively 
broad. Specimens from the waters near the Hebrides ("Thor" stat. 8 (08) and 11 (08)) have, when 7 mm 



20 MEDUSA. I. 



wide, lOO — 140 tentacles, and, when 8 mm wide, 160—180 tentacles; in specimens of this size the ten- 
tacles are very closely packed on the bell-margin. The number of tentacles increases tolerably pro- 
portionally with the diameter of the individual, the average number being as follows: 

Diameter of bell n — 15 mm, 230 tentacles 

— — 16— 20 — 290 — 

— — 21—25 — 390 — 

— — 26—30 — 440 — 

The largest specimen examined ("Michael Sars" stat. 140 {03), east of the Orkney Islands) is 
37 mm wide and has about 500 tentacles; but another specimen, 35 mm wide ("Thor" stat. 180(04), 
south of Iceland) has about 620 tentacles; this is the lar§^est number of tentacles, which I have seen 
in this species. 

The number of ocelli is variable. There is an ocellus on, at least, every 5th of the tentacles. 
Even in one and the same individual the succession of the ocelli is irregular. In a specimen from 
Iceland ("Thor" stat. 241 (04)), about 25 mm wide, the ocelli are, on the whole, found on every second 
tentacle; here and tliere, however, two or even more successive tentacles are provided with ocelli, or 
ocelli are wanting on two successive tentacles. From the Hebrides ("Thor" stat. 8 (08)) we possess a 
number of young individuals, among others two specimens, 7 mm wide, with 100 — 140 tentacles; in 
one of these specimens the ocelli are fairly regularly distributed on every 2nd tentacle, while in the 
other .specimen ocelli are only found on every 4th to 5th of the tentacles; among two specimens, 8 mm 
wide, one has an ocellus on every 2nd tentacle, in the other the ocelli are irregularly distributed 
on every 2ud to every 5th of the tentacles. Specimens from the same locality, 9 and 16 mm wide, have 
ocelli on about every 2nd tentacle. From the "Thor" stat. 11 (08), somewhat to the west of the Hebrides, we 
possess several specimens 8 — 22 mm wide; in most of these specimens there is an ocellus on every 3rd — 
5t]i of the tentacles, though in some specimens every 2nd tentacle bears an ocellus. In two specimens 
from the Orkney Islands ("Thor" stat. 2(08)), 6 — 13 mm wide, the ocelli are fairly regularly distributed 
oil every 5th tentacle. Most of the specimens from Iceland have ocelli on every 3rd — 5th of the tent- 
acles; in not a few cases, however, there is an ocellus on every 2nd tentacle; this is the case, for 
instance, in a 12 mm wide individual and in another, 25 mm wide. — It will be seen, from the facts 
here mentioned, that the number of ocelli stands in no ostensible relation to the size of the individual, 
nor to the locality, in any case as far as the area here dealt with is concerned. 

The question, whether the cordyli may be transformed into tentacles, has been discussed above 
(p. 5). The number of cordyli has been used as a specific character, undoubtedly incorrectly. It is diffi- 
cult, on preserved material, to state with certainty the number of cordyli, as tliey are very apt to drop 
off ou the preservation. With regard to the material, examined by me, the fact is, that in all full- 
grown or nearly full-grown individuals, sufficiently well-preserved, the number of cordyli is equal to 
the number of tentacles. Most of the small sjiecimens are badly preserved. In a specimen, 5 mm wide, 
from the Horns Rev, I have, in some cases, been able to find two cordvli between two successive 
tentacles. 

With regard to the cirri, we may state as in the case of the cordyli: that they frequently dis- 



MEDUSA. I. 21 



appear on the preservation. In most of tlie specimens examined by me cirri are completely absent; 
but in all of the well-preserved specimens a greater or smaller number of cirri are present. In no case 
I have been able to state the number of cirri. 

The Hydroid generation belongs to the genus Cuspidella. As to this point, see B r o w n c 1907, pp. 463 ff. 

This medusa, fairly large and conspicuon.s, widely distributed, and frequently occurring in great 
numbers, has been known from early times, and has been described .several time.s, usually very defici- 
ently, unfortunately, and under many different names. It is, therefore, very difficult to give a reliable 
list of synonyms. The confusion has been further increased thereby that several species, belonging to 
quite other genera or families, have been included in the list.s, e.g. by Haeckcl 1 1879), as demon- 
strated by Browne (1896). Among other species, Tkatcmantias \Cosvietira) pilosella Forbes has frequently 
been identified with '■'■Laod/ce cr7iciata'\ and is even found tinder that name in Be dot: Histoire des 
H\droides'. Browne has refound the Cosmetira pilosella of Forbes and demonstrated, that it belongs 
to quite another group of Leptomedusse. 

If we want to state the correct name of the species, we must do a\va\- willi all descriptions, 
older than 1851; they are all so vague, that the species in question cannot be identified with any 
probability at all. 

The generic naiue Laodicea has been established by Lesson (18431 for the '■^Medusa cruciatcC 
Forskal, called by Lesson ^^ Laodicea criicigera"^ and this generic name has been commonly used since 
that time for the genus here dealt with. The first description of a Laodicea^ sufficienth' clear for 
identification, is the description of ^'•Thaumatitias Kudulatd'^ Forbes and Goodsir 1851^ from the west- 
coast of Scotland. When we admit that none of the forms j^reviously described, which have later on been 
referred to the genus Laodtcca^ may be identified with certainty, there can be no doubt that, according 
to the rule of priority, the correct name of the British Laodicea must be Laodicea undu/ata Forbes and 
Goodsir. The next question is, whether there is any reason, in this particular case, to abandon the 
strict application of the rule, and, as IVIayer (1910) prefers, "to retain an old and familiar name rather 
than to reinstate an unfamiliar one such as L. Hndulatd\ In order to answer this question, we must 
see, how the name of cruciaia has been used in the subsequent period. 

The name Laodicea cruciata was assigned by A. Agassiz (in L. Agassiz i860 — 62, p. 350) to 
Forskal 's medusa, which was, in the same work, identified with Tkaumantias meditcrranca Gegen- 
bauer and joined together with the new species Laodicea calcarata, Z. cellularia (= Thamnaniias 
celbilaria Haeckel 1879, Halistatira cellularia Bigelow 1913), and L. stanroglypka (an apocryphal species) 
to form the genus Laodicea. The specific name cruciata has not been used at all during the subsequent 
period until 1879, when Haeckel united several medusae from the European Atlantic coasts and the Medi- 
terranean under the name of ''Laodice cruciata'. As demonstrated by Browne (1896 p. 482) there is only 

I In "Histoire des Hydroides" 6= periode (1891 a 1900), issued 191S, Bedot has separated ^'Laodicea cruciata" from 
Cosmetira pilosella, but some of the synonyms, placed under the former, do not actually belong to that species. The •'Irene 
viridnla" of Garstang 1S94 seems to be a real Eircne, with distinct stomachal peduncle and with marginal vesicles (according 
to Garstang's description in the quoted paper, p. 215). — "Laodice cruciata" of Haddon iiSS6ci, Garstang (1894), Herd- 
man (1894c), Browne {1895, 1896c, and 1898a) should be referred to Cosmetira piloseUa. 

= The paper was read before the Royal Society of Edinburgh on Jan. 20tli and Febr. 3rd 1851 and printed in the 
Transact, VoL XX, which was completed in 1S53. 



22 MEDUSA. I. 



one single name among Haeckel's 25 synonyms, which really refers to & Laodicea, viz. Thamnantias 
medt/erranen Gegenha.uer. Before Ha eckel, accordingly, the specific name crnciata was very far from 
being commonly used or "familiar", and Haeckel's list of synonyms made the confusion as complete 
as ever. Indeed, I am not able to find a better way out of the mess, than to release altogether the 
name of crnciata and follow the rule of priority, using the name by which the species has first been 
described in a manner which allows a recognition, viz. und/fiata Forbes and Goodsir. This was proposed 
by Browne in 1907, and the proposal was adopted by Vanhoffen in 1911 (p. 365). 

Then we come to the question of the mutual relation between the different species of the 
Genus Laodicca. 

Since new examinations of the medusse belonging to this group have been carried out in later 
years (Browne 1907, Mayer 1910), it may be stated, that the.Mediterranean ^'•Thaumantias mediteryaned\ 
Gegenbaur, the North-American-Atlantic Laodicea calcarata A. Agassiz, and the Tropical-Atlantic 
Laodice itlothrix Haeckel are identical with the North-European Laodicea undulaia (Forbes and Good- 
sir). Mayer is undoubted!)- right, when he refers to the same species the Laodicca tnarania Agassiz 
and Mayer (from the Fiji Islands), a species which, according to the description (1899) is exactly like 
a young niidnlata. Z. indica Browne (from Ceylon) is very like L. laidiilaia, from which it is only 
distinguished (according to Browne 1905b) "in having no spur at the base of the tentacles, in 
having larger ocelli, and perhaps in colour and size", characters to which, as will be understood from 
what is said above, we may hardly assign any specific importance. Cirri are present in Z. indica^ 
though only in small numbers. 

In 1899 A. Agassiz and Mayer described a small medusa from the Fiji Islands, L.aodicca 
fijiaiia; the most characteristic features of this species are the lacking of cirri, the very small number of 
cordyli, and the gonads which, in spite of the small size of the animal (6 mm), were provided with 
"complex diverticulse". Tentacular spurs are not mentioned nor figured. — Maas (1905, Siboga-Exped.) 
describes a Laodicea from the Indian Archipelago and refers it to Laodicea Jijiana, though it is much 
larger, being 20 mm wide ; he is apt to suppose, however, that it belongs to a local variety, to which 
he will apply the name of van indica. Browne (1907 p. 466) find.s, that there is so much difference 
between the two forms, that it will be correct, in any case provisionally, to describe that medusa as 
an independent species, which he calls L. Maasii. As the most decisive difference Browne calls 
attention to the fact, that basal spurs are present on the tentacles of L. Maasii^ whereas such are not 
described m. Jijiana. Thi.s, however, does not contradict the supposition, t\\a.t L. fijiana maybe a young 
stage of L. maasii (it was mentioned above that spurs are not developed in \oung individuals of L. 
undulata from the northern seas). The length of the gonads in L. maasii \s highly variable; Maas writes 
as follows (p. 2(3):" ... ich habe jungere Exemplare gesehen, bei denen die Geschlechtsproducte bis an die 
Peripherie reichten, und altc mit strotzenden Ovarien, die nur etwa die halbe Lange der Radiarcanale ein- 
nahmen." The length of the gonads can, accordingly, have no great importance for specific distinction. The 
structure of the gonads involves more difficulty. In /,. maasii the gonads are provided with simple lateral 
extensions, whereas in L. Jijiana the proximal parts of the radial canals "exhibit complex diverticulas", 
on which the gonads are situated. This is only a difference in degree, it is true, which has no decisive 
importance; but, on the other hand, the specimens of L. Jijiana, in any case the female individuals. 



MEDUSA. I. 2 J 



seem to have contained mature sexual products, in so far as "the ova are prominent, and project out- 
ward in grape-hke clusters over the surface of the genital organs". This, indeed, does not seem to 
suggest, that we have here to deal with young stages. It is not altogether excluded, however, that 
such is nevertheless the case; we know otlier examples, where the eggs of a still voung medusa mav 
develop into a considerable size and give the surface of the gonads a rugged appearance (see, for in- 
stance, the following pages on T/'arupsis). The description, given by Ma as, is so clear and excellent, 
that it cannot be misunderstood. It ma>' be worth while, therefore, to call attention to the fact, that 
Mayer (1910) identifies the two forms, an apprehension which he has not changed in his later work 
(1915, p. 200), after having had the opportunity of examining new material of L. fijiana from tlie 
Torres Straits. 

During the ( lermau Deep-Sea Expedition a small Laodiica was found in the Oulf of Aden ; it 
was 5 mm in diameter and had about 96 tentacles. Vanhoffen (1911) referred this medusa to L. maasii 
Browne. With regard to the size and the distribution of the large ocelli it agrees with I.. I'nd/ca 
Browne, but cirri could not be pointed out with certainty. On the other hand, the presence of spurs 
on the base of some of the tentacles evinces an agreement with /,. viaasii. It is an interesting fact, 
that Vanhoffen did only find spurs on the younger tentacles, whereas such were apparentl\- absent 
in the case of the larger tentacles. Vanhoffen is of the opinion, "dass samtliche Tentakel einen 
Sporn haben, dass er nur wegen der Kriimmung des Schirmrandes haufig nicht sichtbar ist und 
besonders bei alteren Tentakeln undeutlich oder verdeckt wird . ." (1911, p. 221). This agrees ver\- 
well' with what I have observed in Laodicea iindiilata (see above). \'anh6ffen's medusa reminds one of 
the L. bigelowi Neppi & Stiasny (191 1) from the Gulf of Triest, a small medusa (probably young), 
7 mm in diameter with about 70 tentacles, some of which have basal spurs; cordyli, mounted upon 
small bulbs, are found in somewhat smaller number than the tentacles; cirri are wanting. There can 
be no doubt of the identity of this species with Laodicea loidiilata. 

The three forms of Laodicea from the Indo-Pacific region, mentioned above, viz. Jijiaua, 
■maasii^ and iiidica, are undoubtedly nearly related. Their relation to the European Laodicea itndnlata 
may, most adequately, be elucidated through a comparison between the latter and Haas's excellent 
description of "Z. Jijiana var. indica" (= maasii Browne). The description and figure (Taf. V, Fig. 34) 
of the flattened, open, square stomach, the four corners of which are drawn out into four "Zipfel", 
agree exactly with the features found in /.. iindidata. The same holds good with regard to the gonads, 
which, in the case of the North-Atlantic forms, have not been sufficiently thoroughly described up to 
now. Maas mentions "Aussackungen, die nicht allein durch Faltung des die (jeschlechtsprodukte 
tragenden Ectoderms bedingt sind, sondern audi durch entsprechende Aussackungen des entodermalen 
Raumes". Also in this respect we find a complete agreement with the facts, as I have observed them 
in in/d/ilata. The length of the gonads is, in Z. ii/aasii, very variable, being, as a rule, ^ 3 the length 
of the radial canal, but, in some cases, reaching nearly to the circular vessel. The number of tentacles 
seems to be somewhat smaller in L. maasii than in equally-sized individuals of Z. uiidulata; in this 
regard maasii is more in accordance with calcayata and nlothrix. The shape of the tentacles is exactly 
as in tDidulata. Ocelli are said to be found on about three-fourth of the tentacles of maasii; in iindiilata 
the number of ocelli is, as mentioned above, \er\' variable. L. maasii is said to possess a conipara- 



24 



MEDUSA. I. 



tively small number of cordyli; the highly irregular distribution of the cord)li, however, seems to 
indicate, that the number has been greater in the living animal, but that most of the cordyli have 
dropped off, as is often the case in preserved material. — Cirri have not been observed in L. maasii\ 
it is possible, that cirri are really wanting in this form, but, on the other hand, there is an equal 
probability of the want being due to the preservation. As mentioned above, cirri were only ostensible 
in well-preserved specimens of L. undulata, and even then but a very small number were left; more- 
over, it is always very difficult to trace these delicate organs between the densely crowded tentacles. 
Also the above-mentioned L. bigelowi Neppi & Stiasny is said to be devoid of cirri, though its iden- 
tity with the common European form is beyond doubt. The colour of the radial canals, the gonads 
etc. of L. Diaasii is light blue to bluish-green, thus particularly in accordance with the colour com- 
monly found in L. itlotkrix^ a colour which may also be met with in others of the Atlantic forms of 
Laodicea. — Altogether, the description, as given by Ma as, of the East-Indian medusa presents a 
correspondence, accomplished into minute details, with Laodicea in/d/ilata from the north-eastern Atlantic, 
the only feature of distinction being the want of cirri, a feature which, very probably, is due to 
preservation. 

We still have to mention Laodicea pulchra Browne (1902, p. 280) from the Falkland Islands. 
This medusa grows to the size of 25 mm in diameter; in spite of this considerable size it has only 
about 50 tentacles; there are usuall\- 3 — 4 cordyli between each successive pair of tentacles. This is 
evidently a well-defined form, specifically different from all the forms mentioned above. 

Table II. vSynoptic Table of the various forms of Laodicea. 



Name 



undulata 



Occurrence 



ttifditerranfu 
bigelowi .... 
calcarata . . . , 



nlothrix . 

marama 
fijiana . . . 



maasii (ace. to Maas) . . . 



indica (Browne) 

maasii (ace to Vanh.) 



N.-Atlantic, 
Europe 

Mediterranean 

Mediterranean 

N.-Atlantic, 
.\nierica 

Tropical 
Atlantic 

Fiji Islands 

Fiji Islands, 
Torres Straits 

Malayan 
.Archipelago 

Ceylon 
Ciulf of .Aden 



Size 



large, 
up to 37 mm 

not stated 
7 mm 
large 

fairly large 



5-.S nim 
up to 10 in:n 

up to 20 mm 

up to 6 mm 
5 "ii'i 



Cirri 



present 

present 
absent 
present 

present 

present 
absent 

absent 



present 
not stated 



Basal Spurs 



present on 

the younger 

tentacles 

present 

present 

present 

present, but 

not on all 

tentacles 

not mentioned 

not mentioned 

present on 

several 

tentacles 

absent 

present 



Colour 



usualU' reddish or orange, may be 
brownish, purple, blue or violet 

brownish-reddish 

not stated 

usually dark-yellowish, but very vari- 
able, reddish, greenish, or blue 

brownish- white, greenish- white 



bluish or greenish 
bluish, greenish, or violet 

light blue or bluish-green 

not stated 
not stated 



The Table II inchulcs all the different forms of Laodicea described up to now (except 
T.. pulchra), arranged according to their geographical occurrence. It will be seen that all of the forms 
from the Atlantic-Mediterranean area possess both cirri and tentacular spurs, with the exception of Z. 
bigelowi from the Adriatic Sea, in which cirri have not been observed. With regard to the forms from 
the Indo-Pacific region, the organs in question are said to occur in some forms, whereas they are 



MEDUSA. I. 2S 



wanting in others. The predominant colours of the gastro-genital organs are bhiish or greenish in the 
Indo-Pacific forms as also in the Tropical-Atlantic form, whereas the reddish, yellowish, or brownish 
colours are predominant in the North-Atlantic forms; blue, green, and violet may, however, also 
be met with in the latter. 

I am inclined to suppose, that all tlie forms of Laodicea described up to now, with the exception 
of Laodicea pnlchra Browne, belong to one and the same species: Laodicea iindulata Forbes and Good- 
sir, a species which attains its most exuberant development in the North-Atlantic; in the tropical At- 
lantic, the tropical Pacific, and the Indian Ocean tlie species is represented by forms, which may be 
called more or less well-marked local varieties; in some cases the described differences from the typical 
L. nil dn lata may even possibly be due to bad preservation. 

If this view be correct, the G e o g r a p li i c a 1 Distribution of Laodicea itiiditlata is the following : 

1) Atlantic Coasts of Northern Eitrope. — (Z,. iindulata Forbes and Goodsir). — The occurrence 
within this area will be discussed in a more detailed way further below. 

2) A'lediterranean. — Neapel, "occasionally during the winter of 1907 — 08" [L. crnciata, Mayer 
1910). Messina, winter 1852 — 1853 [Thamnanfias ntediterranea, Gegenbauer 1856). Triest \L. cr/iciata, 
Graeffe 1884, Z. bigelowi, Neppi &; Stiasny 1911). Villafranca (L. critciata, ]\I etsch nikof f 1886). 

3) Atlantic Coasts of North-America, south of Cape Cod (/-. calcarata A. Agassiz). — Naushon, 
Vineyard Sovind, between Delaware Bay and Chesapeake Bay, Woods Hole (A. Agassiz 1865, Har- 
gitt 1904, Mayer 1910, Bigelow 1914b and 1915). ^ During the numerous investigations of tlie 
"Grampus" in the Massachusetts Bay Laodicea was never found. Duriug the investigations in July and 
August 1913, ranging from Nova Scotia to Chesapeake Bay (Lat. about 44' / to };]° N.) the species 
was found at four of the southernmost stations, between Delaware Ba}- and Chesapeake Bas- (i. e. Lat. 
37° to 38°26' N.) at the end of July (Bigelow 1915, p. 318 and the list p. 316— 317). 

4) Tropical Atlantic {L. iilothrix Haeckel). — Canary Islands (Haeckel 1879, Vanhoffen 
1912). Bahamas (Mayer 1904). Tortugas, Florida, common during the summer-nu)uths (Mayer 1900). 

5) Fiji Islands, counnon in December {L. fijiana and inaraina, Agassiz and Mayer 1899). 

6) Torres Straits, September— October [L. fijiana, Mayer 191 5). 

7) North-Coast of Ah'zv Guinea and several j^laces in the Malayan-Archipelago [L. fijiana \-ar. 
indica, Maas 1905, L. n/aasii, Browne 1907). 

8) West-Coast of Ceylon {L. indica, Browne 1905). 

9) Gulf of Aden (L. n/aasii, Vanhoffen 1911). 

All records agree, that this species occurs exclusively in the neighbourhood of the coasts. 

Distribution and Occurrence in the nortli-easteru Atlantic. 

The material at my disposal has been collected at 28 different localities, which are here men- 
tioned in the following order: tlie waters .south of Iceland, round Rockall, west, nortli, and east of 
Scotland, North-Sea, Skagerrak. (See Chart II p. 26.) 

I) — Lat. 64°o6' N., Long. 23°i4' W., Faxebugt, Iceland. Julv 2nd 1908. Depth 98 m. Voung-fish 
trawl, 65 m wire. "Thor" stat. 45(08). — i specimen, 12 mm wide. 

The Ingolf-Expediiion. V. S. 4 



26 



MEDUSA. I. 



2) — South of Myrdalsjokel, Iceland. Axxgust 17th 1903. "Michael Sars". — i specimen, 17 mm wide. 

3) — Myri Bugt, Iceland. July 21st 1904. Depth 38 m. "Beskytteren". — 6 specimens, 21 — 
26 mm wide. 

4) — Lat. 64°o4' N., Long. i5°48' W., Myri Bugt. July 24th 1904. "Beskytteren". — 2 specimens, 
18 — 22 mm wide. 




Chart II. Occurrence of Laodicin iimliilata in the northern Atlantic and adjacent waters. 
O Occurrence according to the literature. 



5) — Lat. 64°35' N., Long. ii°45' W., East-Iceland. August 8th 1904. Depth 348 m. Young-fish 
trawl, 20 or 70 m wire. "Thor" stat. 241 (04). — 2 specimens, 25—28 mm wide. 

6) — Lat. 6i°34' N., Long, ig-'os' W., soutli of Iceland. July loth 1904. Deptli 2160 ni. Young- 
fi.sh trawl, 15 or 70 m wire. "Thor" stat. 180(04). — i specimen, 35 mm wide. 

7) - Lat. 63°i2' N., Long. ii°45' W., between Iceland and the Faeroe Islands. August 7th 1904. 
Young-fish trawl, 20 m wire. "Tlior" stat. Da 13. ~ i specimen, 30 mm wide. 

8)— Lat. 59" N., Long. 18° W., between Iceland and Rockall. Olrik. — 3 specimens, 22— 
28 ram wide. 



MEDUSA. I. 27 



9) - Lat. 59°07' N., Long. i3°32' W., north of Rockall. IMobero;. - 5 specimens, 14 — about 
25 mm wide. 

10) — Lat. 58— 59° N., Long. 13-15° W., nortli of Rockall. Rink 1852. — 5 .specimens, about 
22 mm wide. 

11) — Lat. 57°45' N., Long. i3°40' W., near Rockall. August 6th 1910. Young-fi.sli trawl, 50 m 
wire. "Michael Sars" stat. 99(10). — 5 or 7 specimens. 

12) — Lat. 56°58' N., Long. i4°39' W., Rockall Bank. July 7th 1913. "Armaucr Hansen" stat. 2. 
— 200 m wire: 4 large specimens, up to 33 mm wide. — 400 m wire: i large specimen. 

13) — Lat. 54°42' N., Long. i8°44' W., south-west end of Rockall Plateau. July lotli 1913. 
"Armauer Hansen" stat. 4. — 400 m wire: 3 specimens, two very large, one smaller. — fxx) m wire: 
I specimen. — 1000 m wire: 4 large specimens. 

14) — East of Rockall. July 28th 1913. "Armauer Hansen" stat. 17. - .Surface: 9 full-grown 
specimens. — 150 m wire: 3 specimens, two' very large, one smaller. — 600 m wire: 4 specimens, three 
large, one smaller. — 1000 m wire: 3 large specimens. — 1300 m wire: 7 specimens, among which are 
5 very large, being up to 35 mm wide. 

15) Lat. 57°03' N., Long. ii°2o' W., deep channel east of Rockall, May 28th 1908. Young-fish 
trawl, 300 m wire. "Thor" stat. 12(08). — i specimen, 26 mm wide. 

16) Lat. 55°44' N., Long. 9°35' W., north-west of Ireland. June 25th 1906. Depth 1600 in. Vcmng- 
fish trawl, 350 m wire. "Thor" stat. 8g (06). — i specimen, 26 mm wide. 

17) — Lat. 57°52' N., Long. 9°53' W., deep channel east of Rockall. June 8tli 1905. Young-fish 
trawl, 600 m wire. "Thor" stat. 72 (05). — i specimen, about 23 mm wide. 

18) — Lat. 56°56' N., 9°oi' W., west of Scotland. May 28th 1908. Depth 140 ni. Yoiuig-fisii trawl, 
65 m wire. "Thor" stat. 11(08). — 9 specimens, 8— 22 nun wide (8, 11, 13, 14, 14, 16, 21, 21, 22 mm). 

19) — Near St. Kilda. July 5th 1913. "Armauer Hansen" stat. 1. — .Surface: i specimen. — 50 ni 
wire: i specimen. 

20) — Lat. 57°36' N., Long. 7°o5' W., Little Minch. May 27th 1908. Depth 90 m. Young-fish trawl, 
65 m wire. "Thor" stat. 8(08). — 7 specimens, 7—16 mm wide (7, 7, 8, 8, 9, 11, 16 mm). 

21) — Lat. 59°oo' N., Long. 3°34' W., west of Orkney Islands. Ma\- 21st 1908. Depth 66 m. Young- 
fish trawl, surface. "Thor" stat. 2(08). — 2 specimens, 6— 13 mm wide. 

22) — Lat. 6o°55' N., Long. 8°56' W., Faeroe Bank. August 12th 1902. Depth 130 m. "Michael 
Sars" stat. 78 (02). — i specimen, about 15 mm wide. 

23) — Lat. 6i°04' N., Long. 4°33' W., Faeroe-Shetland channel. Jul>- 23rd 1905. Depth 1075 m. 
Young-fish trawl 1000 m wire. "Thor" stat. 124(05). — 1 specimen, about 26 mm wide. 

24) — East of Orkney Islands. June 26tli 1903. "Michael Sars" stat. 140 (03I. — 8 specimens, 25— 
37 mm wide (25, 30, 30, 33, 33, 33, 35, 37 mm). 

25) — Murray Firth. September 4th-5th 1904. "Thor". - i specimen, 23 mm wide. 

26) — Horns Rev lightvessel, west coast of Jutland. September 23rd 1912. Depth 30 m. Verti- 
cal haul, 30—0 m. — I specimen, 5 mm wide with about 48 tentacles. 

27) — 18 miles south of Oxo lighthouse, Skagerrak. May 28th 1907. Depth 510 m. "Thor" stat. 

1074. — 2 specimens. (Plankton Laboratory, Copenhagen). 

4* 



2g MEDUSA. I. 



28) — 12 miles NW. '/4 W. of Hirshals lighthouse, vSkagerrak. October 9th 1904. Depth 640 m. 
Young-fish trawl, in intermediate strata. "Thor" stat. 273. — 7 specimens. (Plankton Laboratory, 
Copenhagen). 

The specimens from the "Michael Sars" 1910 and the "Armaner Hansen" are in Bergens Mu- 
seum, the specimens from the "Thor" stat. 273 and 1074 are in the collection of the Plankton Labora- 
tor}' in Copenhagen; the other specimens are all in the Zoological Museum of Copenhagen. 

The information, given in the literature, on the occurrence of Laodicca itndiilata in the North 
Atlantic area are rather few and scattered and, moreover, not always reliable, in so far as the species 
has frequently been confounded with Cosuictirn pilosclla Forbes. 

The type-specimens of F'orbes and Good sir were found in the Minch Ijetween Scotland and 
the Hebrides "on a very warm day, when the sea was very calm . . .". 

^'■Laod/cc cr/ta'atn ( Tliaiiiiiantias pilosclla Forbes)" has been recorded from St. Andrews Bay by 
Mcintosh (1888) and by Crawford (1891) who states, that it "swarmed throughout August and 
continued in diminishing numbers till November". After recording the species under the name quoted 
above, the latter author adds: "with marginal cnri and club.s". This seems to show, that the recorded 
species is really Laodicca miditlata and not Cosiiictira pilosclla. 

During the investigations of Browne in the Firth of Clyde 1901—02 Laodicca itiidulata was 
not fomid. 

According to B r o w n e (1900, p. 720) the .species has been found several times in the neighbourhood of 
Valencia Harbour, Ireland. In 1895 it was found in April and July, in 1896 from July to the beginning 
of September; in 1897 it appeared in May and was fairly common in August and September and again 
in November, whereafter it disappeared. In 1898 it was found from June to November and was very 
abundant during July and August. Browne adds: "This species has not often been recorded in Bri- 
tish .sea.s". In the paper here quoted Browne calls the species with the name of L. calcarata. — It 
was also at Valencia Harbour that Miss Delap succeeded in rearing L.aodicca from the Hydroid Ciispi- 
dclla costata Hincks, in June 1906 (Browne 1907, p. 464). 

The medusa recorded by Browne 1895 (Report on the Medusse of the L. M. B. C. District) as 
'■^Laudicc cruciata'^ belongs to Cosmetira pilosclla Forbes. But in the same paper (p. 276) is mentioned 
a specimen of "■/Modice calcarata L. Agassiz", found at Port Erin on May 5th 1894, a young specimen, 
5 mm in diameter "... with about 30 tentacles, and cirri of both .shapes" (i.e. filiform cirri and cor- 
dyli). "It corresponds to the descriiDtion given by Agassiz". This medusa has, undoubtedly, been a 
Laodicca undulata, which .species may, accordingly, be found at Port Erin. 

From Plymoutli ''Laodice cruciata'" has been mentioned by Garstang (1894, p. 215), but also 
in this case the medusa in question has actually been Cosmetira pilosclla Forbes. Browne (1897 b) 
gives a list of meduste, found at Phniouth during September 1893, 1895, and 1897. Laodicca is not 
mentioned in that list. Neither is it recorded in the "Plymouth Marine Invertebrate Fauna" 1904, whereas 
''pMchilota pilosclla (Forbes)" is said to be connnon every summer in the neighbourhood of Plymouth. 

Nevertheless, Laodicca undulata actually occurs in the British Channel. In the British Museum 
of Natural History in London I have seen two specimens from Phmonth, and it is recorded from the 



MEDUSA I. 2Q 



Channel (under the name of Laodicc calcarata) in the International Plankton Catalogues (Catalogue, 
1906, 1909, and 1916). We have to he very cautions, it is true, in employing these catalogues, as the 
identifications of the species have, as a rule, not been made by specialists; in the present case, how- 
ever, I believe the identification to be correct. In one particular instant I have been able to verify the 
identification directly, some specimens being present in the type collection of the plankton la])oratory 
in Copenhagen. — During the years from 1903 to 1908 the .species has been taken in the Channel 
almost every year in the month of August, and sometimes also in May; only once it was found in 
November (1905). It was found in the Bristol Channel in August 1905, 1906, and 1907, and in May 
1908. It has also on one occa.sion been found in the North vSea off the coast of Belgium, viz. in Au- 
gust 1905. 

As far as I anr aware, Laudiccn nndnlata has never been recorded from the east coast of Great 
Britain south of St. Andrew.s. 

Neither has it been mentioned from Heligoland. 

I have worked through a very considerable material of ])lanktou from the Horns Rev light- 
vessel off the .southern part of the west coast of Jutland, l)nt I have only found one single, .small 
specimen of this species. 

It seems also to be scarce in the Skagerrak, in so far as it has ouI\- been observed twice in 
that sea; it does not penetrate into the Kattegat. 

I have never seen this species recorded from the west coast of Norwa\-, and it seems, on the 
whole, to be altogether lacking in the Norwegian Sea '. 

Nor is it known to occur off the Atlantic coasts of Europe .south of the British Channel. 

If we compare the records of the literature with the data derived from the material examined 
by me, we will gain the following general picture of the horizontal distribution of Laodicea iindulata 
in the North-East Atlantic area: The species occurs off the southern coasts of Iceland, is numerous 
around the Rockall plateau and Scotland; it is also found, though apparently in smaller quantities, off 
the western coasts of Ireland and England, in the Channel, and in the south-western part of the North 
Sea. Finally it may be found, occasionally, off the western and northern coasts of Jutland. 

All records agree, that this species does not occur in an)- great distance from the coasts, that 
the distance from the shore, accordingly, sets a limit to the horizontal distribution. ( )n the other hand, 
the actual depth is without importance with regard to the occurrence. Some of the specimens 
here dealt with have been taken in shallow water near the coasts or above the Rockall Bank, 
others have been found above very deep water, as for instance on the "Thor" stat. 180(04), where the 
depth was 2160 m, and several specimens have been found in the Rockall Channel, the Faeroe-Shet- 
laud Channel, and the Norwegian Channel. 

With regard to the vertical distribution we will find, that the species may occur in very diffe- 
rent depths below the surface, it having been found in all strata between the surface and about 800 m 
below the surface. The results of tlie cruise of the "Armauer Han.sen" in 1913 are particularly instruc- 
tive with regard to the occurrence of this species. Laodicea uiidulata was lacking on all of the 

») Hartlaub (1900, p. 172) mentions numerous specimens "der schonen, scheinbar magenlosen /Modice cruciata", found 
during the expedition of the "Olga" at Tromso (northern Norway) on June 28th 1S98. If the identification be correct, we have 
here an isolated find of high interest. 



,0 MEDUSAE. I. 



western stations of this expedition, these stations being situated too far from land; on the other hand, 
it was found on all of the eastern stations, stat. i, 2, 4, and 17. But in these localities, all in compara- 
tively short distance from land, the species was found down to tlie very greatest depths, in which 
hauls were made, and by no means in small numbers. Particularly interesting is the station 17 in the 
deep channel between Rockall and Scotland ; at this station 9 specimens were taken at the surface, 
7 specimens in abotit 800 ra depth, and a number of specimens about 100, 400, and 650 m below the 
surface. On this locality, accordingly, the species was fairly common in all strata, at least as far down 
as about 800 m below the surface. 

Young specimens are, however, found in the upper water layers exclusively, whereas large and 
middle-sized individuals may be met with in all depths. In the material at my disposal young indi- 
viduals are present from the following localities: 

Loc. Nr. I. "Thor" stat. 45 (08). July 2nd 1908. Surface. — i specimen, 12 mm. 

— - 18. — — 11(08). May 28th 1908. About 40 m depth. — 9 specimens, 8—22 mm. 

— - 20. — — 8(08). May 27th 1908. About 40 m depth. — 7 specimens, 7— 16 mm. 

— - 21. — — 2 (08). May 2ist 1908. Surface. — 2 specimens, 6 — 13 mm. 

— - 26. Horns Rev. September 23rd 1912. 30—0 m. — i specimen, 5 mm. 

These localities are all situated very near land. It will be observed, moreover, that most of the 
young specimens have been found at the end of May; one specimen was taken at the beginning of 
July in Faxebugt on the west coast of Iceland, and one specimen, the smallest which I have seen, 
was found in September off the west coast of Jutland. — Larger individuals may also be met with 
early in the year. Thus on May 28th 1908 (Loc. Nr. 15) a specimen, 26 mm wide, was found in about 
200 m depth, and the very largest among the specimens observed, 37 mm wide, was found together 
with 7 other specimens on June 26th 1903 east of the Orkney Islands ("Michael Sars" stat. 140(03), 
depth not .stated). Most of the large specimens were, however, taken in July and August. This 
agrees very well with the statements in the literature. According to these the .species appears off the 
British coasts in May, more seldom in April (Valencia Harbour, Browne 1900), is common during the 
summer months, and disappears in October or November. The material, examined by me, gives no 
information as to how late in the autumn the species may be met with in the area investigated, be- 
cause none of the expeditions, the material of which has been at m>- disposal, has worked in these 
regions later than in October, most of them only during the summer months. 

According to the above .statements Laodicea zmdulata is, in the North-East Atlantic area, a 
sununer form, deliberated from the littoral hydroid Cuspidella in the spring or the first summer months, 
reaching its full size in the warm months, and disappearing in the late autumn, after having accom- 
pli.shed its breeding sea.son; probably the planula larva: attach themselves in the autumn and develop 
into the hydroid Cuspidella, which passes the winter and sends out its medusa generation in the 
next spring. 

Also off the east coast of North America Laodicea nndulata is a summer form, occurring from 
June to the beginning of the winter, being most frequent in July and August. — In the Mediterranean, 
on the other hand, it is found during the winter. 



MEDUS.E I. 
— ._ o 



Genus Ptychogena A. Agassiz. 
Ptychogena lactea A. Agassiz. 

Plate HI, figs. 1-6. Textfig 5. 

Ptychogena lactea A. Agassiz 1865. North Anieiicaii Acalepha;, p. 137, figs. 220—224. 

— — Haeckel 1879. System der Medusen, p. 147. 

— piiunilata Haeckel 1879. ibid. p. 148. 

— — — 1881. Tiefsee-Medusen der Challenger-Rei.se, p. 6. Taf. II. 

— lactea A. Agassiz 1888. Bull. Mus. Comp. Zool. Harvard Coll. Vol. XV, p. 128. 

— pinnulata Levinsen 1892. Mediiser etc. fra Gronlands Vestkyst. — Vidensk. Meddel. Natur- 

hist. Foren., 1892, p. 145. 

— — Aurivillius 1896. Plankton der Baffius Bay nnd Davi.s' Strait. — Festskr. Willi. 

Lilljeborg tillegnad, p. 198. 
lactea Vanhoffen 1897. Fauna und Flora (ironlands. — Drygalski's Gronland-Exped. 
Bd. II, p. 273. 

— piniiiilata Gronberg 1898. Hydroid-Mednsen des arktischen Gebiets. — Zool. Jahrb. Bd. XI, 

P- 465- 

— — var. Linko 1904 b. Zool. Studien im Barents-Meere. — Zool. Anz. Bd. XX\'III, 

p. 217. 
lactea Browne 1907. Revision of the Laodiceidse. — Ann. Mag. Nat. Hist. Ser. 7. Vol. XX, 

P 473- 

— — Mayer 1910. Medusa; of the World, p. 215. 

— — Bigelow 1913. Medusae . . . N. W. Pacific. — Proceed. U. S. Nat. Mus. \'ol. 44, p. 28. 

— — Kramp 1913. Medusie . . . "Tjalfe" P^xped. — Vidensk. Meddel. Dansk Naturhist. 

Foren. Bd. 65, p. 268. 

— — 1914- Conspectus Faunae Groenlandicce, p. 422. 

Description of a full-grown specimen from the south coast of Disco, Greenland, "Tjalfe" 
Exped. Stat. 125. 

Diameter (the specimen is preserved in alcohol) about 90 mm, height of the bell about 30 mm. 
The gelatinous substance is ver}- thick, 10 mm at the apical point; the thickness is almost equal 
throughout the greater part of the bell; only in the peripheral part, within a short distance from the 
bell-margin, it is evenly diminishing towards the latter. The stonuich is quadrate, attached to the 
subumbrella along the arms of a perradial cross, so that there are four interradial, triangular pouches 
between the dorsal wall of the stomach and the subumbrella. The length of the sides of the stomach 
is 20 mm. The prismatic mouth-tube is short, hardly 10 mm long. The mouth-opening is quadrate; the 
four perradial corners are dilatated into four quite short lips. The mouth-edge is faintly folded. The 
perradial cross, mentioned above, along the arms of which the stomach is attached to the subumbrella, 
is seen on the inner side of the dorsal wall of the stomach as four ciliated grooves; in this specimen 
the grooves do not meet exactly in the centre (see Plate III, fig. i); the grooves are centripetal con- 
tinuations of the dorsal wall of the radial canal.s. The proxinuil two-thirds of the 4 radial canals are 



32 



MEDUSA. I. 



funnel-shaped, with a wide opening into the corners of the stomach; the distal one-third of the radial 
canal is a narrow tube, communicating with the narrow circular vessel. The umbrellular part of the 
funnel-shaped canal is narrow, and from this part issue a large number of lateral folds or branches, 
perpendicular to the main canal. The umbrellular walls of these lateral folds are attached to the sub- 
umbrella, whence the folds hang as perpendicular lamellae, the ventral edges being free. Below the narrow, 
lamelliferous part of the radial canal is the wide, funnel-shaped part, mentioned above, reaching out- 
wards nearly to the outermost (distal) lateral folds, gradually narrowing outwards and terminating 
in a point. The narrow dorsal part is separated from the wide ventral part by a longitudinal fold on 

each side (Plate III, figs. 2 and 3). These two folds continue in a centri- 
petal direction in the dorsal wall of the stomach nearly to the centre 
along both sides of each of tlT£ ciliated grooves (Plate III, fig. i). Towards 
the distal end of the funnel-shaped part the folds are gradually' tapering; 
in the distal part of the folding system there is, accordingly, no complete 
separation between the ventral and the dorsal part of the canal. Thus a 
differentiation of the gastro-vascular system, similar to that in Laodicea 
iiiidiiltifa^ is established in this species. Probably the food is received and 
dissolved in the wider, ventral part (I have found half-digested copepods 
therein); the dorsal part onh- communicates with the \entral part for a 
short distance near the distal end of the funnel-shaped part. Proximally 
the dor.sal part opens into the dorsal wall of the stomach through a 
narrow opening, distally it passes into the narrow, tube-shaped part of 
the radial canal, free of gonads, through which the dissolved nutritive 
substances, which have been carried from the funnel-shaped part into 
the dorsal part, are transported further into the circular vessel. 

Seen from the aboral side the systems of transversal folds form 

together four elliptical figures, commencing at a short distance from the 

^.. ,„ , , , » , ■ corners of the stomach. In the present specimen the length of the ellipti- 

rig. 5. I lychogi-na lac tea A. Aga.ssiz. ^ '■ '^ ' 

A radial canal with it.s branches cal figures is about 24 UHu, the largest breadth about 19 mm, the longest 

and K""ads, seen from tne apical ^ > o 7)0 

side From a specimen from (middle) of the lateral branches being about o mm long, perpendicularly 

Rilenbenk, dreenland. & / ») 1 1 . 

to the main canal. Within this part of the radial canals there are alto- 
gether 20—25 folds on each side of tlic main canal. Besides these closely set folds there are some 
short, isolated folds in the lateral walls of the grooves in the dorsal wall of the stomach (see textfig. 
5, which has been drawn from anotiier specimen): Each of the lateral branches of the radial canals 
has the shape of a flat, perpendicularly placed pouch, the dorsal edge of which is attached to the 
sul)unibrclla along a narrow line, and which o])ens into the main canal by a perpendicular fissure in 
the narrow, dor.sal part of the canal (Plate III, fig. 4). In the walls of these pouches the gonads are 
developed. The gonads (Plate III, fig. 51 surromid the pouch completely except in the line, by which 
the latter is attached to the sul)unil)rella. Thus the gonads on the two sides of the pouch communi- 
cate around the free (\entral and distal) edges of the pouch. Moreover the gonads of two successive 
l)ouches communicate proximalh' in the iJerpendicular edge between the openings of the two pouches 




MEDUSiE. I ,^ 



into the main canal. Accordingly, each of the four radial canals of the medusa has actually only two 
gonadial bands, separated in the median line of the canal, but each of these bands is folded in a 
complicated manner. The free edge of each of the pouches gives rise to a row of papilla; of different 
length (Plate III, fig. 2). The papillse are hollow; they are extensions from the lateral branches of the 
radial canal, and their lumen communicates with the lumen of the latter (Plate III, fig. 5). The papillae 
are more closely set in the distal part of each of the lamellae; in the middle part they are more dis- 
persed, and in the proximal part the edge of the lamella is smooth (Plate III, fig. 2). On the shorter 
(younger) lamellce the smooth part is comparatively long, only a few papilke being present, and these 
are distally .situated; on the longest (oldest) lamella; the smooth part is quite short; on the quite young 
lamella; no papillse are found, the edge is quite smooth. — The oldest lamellae are in the middle part 
of the system; the proximal and the distal lamellae are the younger. New lamellae are formed, how- 
ever, not merely proximally and distally, but also intermediary between the older lamellae in any 
spare room in the system. — The side-walls of the lamellae are, as a rule, not quite plane, but are 
more or less uneven. We may even, occasionally, find a secondary branch, forming an acute angle 
with the mother-branch. — In the present specimen the ventral, funnel-shaped part of the radial canals 
reaches nearly to the distal end of the folded system. 

The bell margin carries a large number of tentacles and cordyli. In the present specimen there 
are 400 — 500 tentacles. Each of the tentacles has a somewhat compressed bulb, about 2.5 mm long; 
this bulb is somewhat broader distalh' than proximally. Its outer (abaxial) edge is convex, the inner 
(adaxial) edge is straight or faintly concave (Plate III, fig. 6). The distal end of the bulbus bends 
sharply inwards (adaxially) at the point of transition into the thread-like part of the tentacle; very 
soon the latter bends sharply outwards. The tentacular bulb is hollow; its lumen opens like a funnel 
into the circular vessel. On the abaxial side of the basal part of the bulb there is a short, conical 
protuberance (a rudimentary tentacular spur) extending into the gelatinous substance of the ex- 
umbrella (Plate III, fig. 6). — The cordyli are small; in the present specimen they are about '/r. the 
length of the tentacular bulbs. They alternate fairly regularly with the tentacles, forming a row a little 
inside the row of tentacles. Each of the cord>li has the shape of a lengthened club, mounted upon a 
small tubercle closely outside the base of the velum. The cordyli are hollow, but their lumen is very 
narrow, and in fully developed cordyli it is apparently always separated from the circular vessel, the 
lumen of the peduncle being quite obliterated. — This specimen seems to represent the fully developed 
stage of growth, in so far as the tentacular bulbs are all of equal size, and the cordyli alternate with 
the tentacles and are all situated on small tubercles. 

The velum is well developed but weak. 

As far as I am aware, this individual is the largest specimen of Ptychogcna lactea hitherto 
described. In younger individuals there are a smaller number of lateral folds on the radial canals, and the 
free edges of the lamella; carry a smaller number of papillae; in specimens, less than about 35 mm in dia- 
meter, the edges are quite smooth. In younger specimens the funnel-shaped extensions of the corners 
of the stomach do not reach the distal ends of the gonadial part of the radial canal.s. The lateral 
folds, which separate the dorsal part of the radial canal from the ventral part, are not developed in 

The Ingolf-Enpediiion. V. 8, " 



34 



MEDUSA. I. 



young individuals. The secondary branching of the lateral branches of the radial canals seems to be 
a feature of individual variation with no relation to the developmental stage of the specimen. 

The smallest specimen, which I have examined, was found near Jakobshavn in Greenland. It is 
14 mm in diameter. The state of preservation is not good, especially the stomach is much destroyed. 
The bell seems to have been comparatively higher than in grown-up individuals; in the present 
condition of the specimen the height is 8 mm. The length of the folded parts of the radial canals is 
about 3.5 mm, the largest breadth about 2—2.5 mm. In each of the folding systems 5—6 pairs of lateral 
folds are present; they confirm the above statement, that new lateral branches are developed not only 
proximally and distally, but also intermediary ; there are no secondary branches. The free margins of 



Table III. Synopsis of the specimens of Ptychogfina lactea examined. 





u 
u 

« Oh 


Height of 
specimen 




2 


Distance from the 

centre to the 
beginning of the 
closelj'-folded part 


Length of the 
closely-folded part 


Largest breadth 
of the closely- 
folded part 


Number of 

primary folds in 

the closely-folded 

part 


Length of the 

distal part of the 

radial canals, free 

of gonads 


Number of 
tentacles 


Number of 
cordyli 


Remarks 




mm 


mm 


mm 


mm 


mm 


mm 




mm 








3 


90 


30 


20 


11 


25 


19 


40-50 


10 


400—450 


same 

number as 

tentacles 


Lamellie with papillae, a few with 
secondary branching. 


— 


70 




14 


II 


13-15 


^3 


37-43 


13 — 14 


... 




Largest lamelhe with about 15 pa- 
pillee, no secondary branching. 


2 


68 








14—16 


12—13 


41—49 








Lamellae with as many as 5 — 6 pa- 
pillae; secondary branching. 


I 


50 




II 


10 


10-12 


8-9 


25-28 






. . . 


Papillae present; secondary branch- 
ing. One of the radial canals ab- 
normal, its dimensions not inclu- 
ded in the table. 


7 


40 




















Secondary branching. Fairly long 
papillae 


9 


35 


20 






8 


7-5 


about 25 


7 




about equal 
to number 
of tentacles 


Edges of lamellae smooth ; secondary 
branching of a few lamella;. Only 
one gonadial system measured. 


4 


14 


8 






3-5 


2-2.5 


10—12 


2-3 


60—80 


more nume- 
rous than 
tentacles 


No papillie; no secondary branching. 



the lamella; are smooth. The length of the distal part of the radial canals, free of gonads, is 2—3 mm. 
The number of tentacles cannot be stated exactly, but there are about 15—20 tentacles in each qua- 
drant. The cordyli are somewhat more numerous than the tentacles (compare Bigelow 1913, who 
states that there is a comparatively larger number of cordyli in young specimens than in older ones). 
vSome of the cordyli are situated on quite small tubercles as in the large individual, but some others 
arc mounted ujion large, thick bulbs, very like tentacular bulbs of half size; still others are placed 
in a manner intermediary between these two extremes. 

In order to illustrate the variation and development of the .species I have worked up the 
above synoptic table (Table III) of the specimens examined by me. — Most of the specimens are 
badly preserved, so that especially the number of tentacles cannot be stated. As will be seen from the 
synopsis,, the .shape .of the folded part of the radial canals is subject to much variation; it may be 



MEDUS-4J. I. ,e 



nearly circular in outline, as in the specimen from the Kara Sea (locality No. 9) and the 70 mm wide 
specimen from the "Tjalfe" stat. 125, or it may be more lengthened, elliptical. 

From the "Tjalfe" stat. 171 we have a specimen, 50 mm wide, in which the canal system is 
abnormally developed. One of the radial canals is t)ifurcate pro.ximally near its point of issue from the 
stomach. Each of the two branches has its own system of lateral branches and gonads, and the two 
systems do not touch each other. The one system is somewhat smaller than the other and diverge 
somewhat more from the perradial direction. This "secondary" canal has, i)robably, not reached to the 
circular vessel; this cannot, however, be stated with certainty. The gonads in the "secondary" sy.stem 
are on the same stage of development as the others, though tlie lamella; are .somewhat shorter. 
Another radial canal in the same specimen is bifurcated distally. The folded gonadial part has nearly 
the normal shape, but the distal end of this part gives rise to two narrow, divergent canals, running 
to the circular vessel. One of the lateral branches of this gonadial system is twice dichotomically branched. 

It has been acknowledged long ago, that the difference between Ptyc/iogena lactca Agassiz and 
Ptychogoia piiniitlata Haeckel depends on development and variation. H a eckel's description is based 
on two specimens from the Atlantic north of Rockall and a fragment of a specimen, found by the 
"Challenger" expedition in the neighbourhood of Halifax. The two first mentioned specimens are in the 
Zoological Museum of Copenhagen; thus I have been able to examine these specimen*;. Haeckel 
states that the abaxial side of the tentacular bulbs is concave, whereas the adaxial side is convex, 
and he gives a drawing in accordance herewith (Haeckel 1881, Plate II, fig. 4). Actually the fact is 
the contrary (see Plate III, fig. 6). Moreover the cordyli hiive been drawn too large, especially too thick; 
they are fairly thin in this specimen. — There is another specimen from the same locality, very badly 
preserved. As the specimen has hitherto been labelled "7y?rt/////c/;///>?i'", and as Haeckel only mentions 
two specimens from this locality, this specimen has, I think, not been in the hands of Haeckel. 

Bigelow's record of Ptychogetia lactea from the north-western Pacific (1913) is of considerable 
interest, partly owing to the statement of the occurrence of this species in the Pacific, partly on account 
of the observation, that the young specimens have a comparatively larger number of cordyli than the 
full-grown individuals; a specimen with about 50 tentacles had about 160 cordyli. 

Among other species, which have been referred to the genus Ptychogena, I have already men- 
tioned (p. 13 — 14) ^'Ptychogena eryfkrogoiioii'' Bigelow and ''Ptychogena Heriwigr Vanhoffen, which both 
belong to the genus C/iroinatonema. 

The medusa, described by Ma as (1893) as Ptychogena longignna from the north-eastern Atlantic, 
has not been found since it was described by Maas, though numerous collections have been made in 
the same region. Setting aside that ocelli are not mentioned in the description, this reminds one to a 
considerable degree of Laodicca nndulnta^ and I am, in fact, very much inclined to think that this is 
actually the species described by Maas. 

Torre y (1909, p. 13) describes a species from San Diego, California: Ptychogena cali/ormca. 
Two young specimens were found, 10 mm in diameter by more than half as high, with about 48 tent- 
acles, 1 — 5 cordyli between every successive pair of tentacles, gonads with 12 — 14 fold.s. This is 
undoubtedly a Ptychogena, but I dare not decide, whether it is a distinct species or only young 

individuals of Ptychogena lactea. 

5* 



36 



MEDUSA. I. 



Ptychogena antarctica Browne (1907, more thoroughly described in 1910, p. 29) is distinguished 
from Ptychogena lactea by the fact that the gonadial lateral folds are shorter and not attached to the 
subumbrella, and by the colour, the base of the tentacles being, according to Browne, provided with 
red entodermal pigment; according to Vanhoffen (1912), who has refound the species in the material 
from the German South-Polar expedition, the organs are dark coffee-brown. There is one cordylus be- 
tween every successive pair of tentacles, and in some of these cordyli Browne found nematocysts (see p. 4). 




Chart III. Occurrence of Ptychogena lactea A. Agassiz in the northern Atlantic and adjacent arctic waters. 
denotes the southern limit of the occurrence in the Barei^ts Sea, according to Linko. 



The hatching 



Vanhoffen (1912, p. 366) describes another species, Ptychogetia aiirea^ from four small speci- 
mens with about 32 tentacles and gold-yellow gonads with mature sexual products. Cordyli are not 
present. I am not convinced that this medusa belongs to the genus Ptychogena^ but I will not deny 
the possibility. 

I have had at my disposal for examination 12 specimens of Ptychogena lactea from 9 different 
localities. In the following list I have also included some non-preserved specimens from Godthaab 
Fjord, Greenland, found by the "Tjalfe" expedition; in the journal of the expedition they are shortly 
but clearly described, so much so thai they may be identified with complete security. 



MEDUSA. I, 



Material (ste Chart III). 
Greenland: 

i| — Lat. 70°4i' N., Long. 52°07' W., Umanak Fjord. August 6th 1908. Depth 727 in. Ringtrawl, 
800 m wire. "Tjalfe" stat. 171. — i specimen, about 50 mm wide. 

2) — Ritenbenk, Disco Bay. Bergen da 1. — i specimen, about 68 mm wide. 

3) — Lat69°i7'N., Long. 52°i4' W., south coast of Disco. July i6th 1908. Depth 430-440 m. 
Ringtrawl, 550 m wire. "Tjalfe" stat. 125. — 2 specimens, 70 — 90 nmi wide. 

4) — Jakobshavn, Disco Bay. Bergendal. — i .specimen, 14 mm wide. 

5) — Lat. 66°55' N., Long. 54°37' W., 20 miles west of Holstensborg, August 23rd 1908. Depth 
66 m. Ringtrawl, 80 m wire. "Tjalfe" stat. 211. — i specimen, about 40 mm wide. 

6) — Godthaab Fjord, Lat. 64°!!' N. August 30th 1908. Ringtrawl, 120— 80 m wire. "Tjalfe" stat. 
234. Ringtrawl, 30 m wire. "Tjalfe" stat. 235. — Some few specimens, not preserved. 

7) — Greenland, without further details. "Fylla". — i specimen, about 40 mm wide. 
Atlantic: 

8) — Lat. 59°o7' N., Long. i3°32' W. Mob erg. — 3 specimens, two of which are the type spe- 
cimens of Ptycliogoia piiniiilata Haeckel. 

Kara Sea: 

9) — Kara Sea, without further details. "Dijmphna". — i specimen, about 35 mm wide. 
Polar Sea: 

10) — Cape Stephens, Franz Joseph Archipelago. H. Fisher. — i specimen. 

The last-mentioned specimen have I seen in the British Museum of Natural History in London, 
the others are all in the Zoological Museum of Copenhagen. 

Moreover the species has been recorded from the following localities: Near Jakobshavn, Green- 
land (Vanhoffen 1897, p. 273). — Eastern and western part of the Barents Sea north of Lat J2°Tp' N. 
(Linko 1905, p. 217). — Near Hahfax, Lat. 42°o8' N., Long. 69*39' W. ("Challenger", Haeckel 1881, p. 6). 
— Nahant, Massachusetts Bay (A. Agassiz 1865, p. 137). — Bering Sea, Sea of Okhotsk, and off the 
east coast of Hokkaido, Japan (Bigelow 1913, p. 28). — Moreover Levinsen (1892, p. 3) mentions 
this species from Iceland from the authority of Faber. In his "Naturgeschichte der Fische Islands" 
(1829) Faber describes 10 .species of medusse, but I am not able to see, how any of his descriptions 
could refer to Ptychogena lactea. 

The places of occurrence off the west coast of Greenland are all near the coast in the cold 
water. No specimen has been found in that part of the Davis Strait, which is occupied by the com- 
paratively warm Atlantic water. 

The data now in hand give us the following general picture of the horizontal distribution of 
this species: 

Ptychogoia lacfca has its home in the arctic regions, and has probably a circmnpolar distribu- 
tion. It is found off the west coast of Greenland between Lat. 64°!!' and 70°4i' N., further in the 
Barents Sea, the Kara Sea, and near Franz Joseph Archipelago. Only occassionally it has been found 
in the Atlantic outside the arctic region, viz. north-west of Scotland' and in the Mas.sachusetts Bay. 
In the Pacific it follows the Kamtschatka Current southwards as far as the northern part of Japan. 

' If the statement of that locahtv is correct. 



38 



MEDUSA. I. 



A. Agassi/, was of opinion that Ptychogena lac tea was a deep-water species, and he des- 
cribes, how it is very rapidly killed by the influence of the light and the higher temperature of the 
surface water. In the Massachusetts Bay, however, the conditions are so unfavourable for this species, 
that its occurrence in this area gives no reliable information with regard to its habits under normal 
conditions. Bigelow (1914 a, p. 98) states as follows: "The occasional occurrence of Arctic pelagic 
organisms in Massachusetts Bay and the Bay of Fundy, such as the medusa Ptychogena and the 
ctenophore Merfeiisia, neither of which has been able to establish itself in the Gulf, shows that there 
are occasional indraughts of the vSt. Lawrence water into the latter. But ... its influence is either 
sporadic, or seasonal, not constant." A. Agassiz (1888, p. 128) repeats the statement, that Ptychogena 
lactea probably is a deep-sea medusa. On the other hand, Vanhoffen (1897, p. 273) mentions a speci- 
men, found frozen up in the ice in the neighbourhood of Jacobshavn in Greenland, and he remarks 
(p. 274): "Dieses Vorkommen scheint mir nicht dafiir zu sprechen, dass diese Art eine Tiefsee-Meduse 
ist, wie angenommen wurde". Browne (1907, p. 473) likewise remarks: "There is no trustworthy evi- 
dence that it is a deep-sea^ form". 

As far as the material, examined by me, is concerned, the depth in which the specimens have 
been found is only stated in the case of the material, brought home by the "Tjalfe" expedition. The 
statements of this expedition show that the species may be found in very different depths off the 
west coast of Greenland. In Umanak Fjord, which is more than 700 m deep, and the deeper water 
layers of which have a temperature of about 1° C, Ptychogena lactea was found in about 500 m depth. 
In Disco Bay, the lower strata of which consist, likewise, of cold water, the species was found about 
350 m below the surface, at a temperature of o°.9 C. On stat. 211, on the Store Hellefiskebanke, it 
was found about 50 m below the surface; we have no hydrographical data from the station itself, but 
judging from observations from neighbouring places, made on the same day, the temperature in the 
depth in question must have been about 1.5 — 2° C. Godthaab Fjord is one of the fjords, into which 
the comparatively warm water-masses of the Davis Strait are not admitted on account of a threshold 
in the mouth of the fjord. On August 30th 1908, when the temperature of the water in the fjord had 
been under the influence of the conve\ance of a whole summers warmth, the temperature was found 
to be gradually decreasing from 2°.8 at the surface to i°.3 near the bottom (77 m). Ptychogeiia lactea 
wa.s, in this fjord, found both near the surface (30 m wire) at a temperature of about 2°.5, and in 50 — 
70 m depth at about i°.4 C. As the collections of the "Tjalfe" expedition were made with open nets, 
we may, of course, not be absolutely certain, but that a few animals may have been captured during 
the hauling up of the net through higher water layers. With regard to the stations 171 (Umanak 
Fjord) and 125 (Disco Bay) it should be remarked, however, that hauls where also made in higher 
water layer.s, and no specimens of Ptychogena were taken in these hauls; it is most probable, there- 
fore, that tlie specimens from these stations have actually been captured in the fairly great depths 
here stated. 

The most important factor determinating the distribution of Ptychogena lactea off the we.st 
coast of Greenland seems to be the temperature of the water, the species being only found, where the 
water is cold. 

As far as the other biological habits of the species are concerned, nothing po.sitively can be 



MEDUSA I. 



Stated. The specimens from the "Tjalfe" expedition were all found in July and August With regard 
to the other material no information of the time of collection are present 

Genus Staurophora Brandt. 
. --jr Staurophora mertensii Brandt 

Plate I, fig. 9; riate II, figs. 9—10; Plate III, fig. 7. 

Staurophora mertensii Brandt 1838. Schirmquallen. - Mem. Acad. Imp. Sci. St Petersb. Ser. 6. Tom. 4. 

— p. 400. Taf. 24—25. 

— laciiiiiita L. Agassiz 1849. Contrib. Nat Hist, of the Acalepha; of North America. — 

p. 300. PI. 7. • ■■ 

Oceania wulticirratu M. Sars 1851. Beretning . . . Reise i tofoten og Finmarken. — Nyt Magazin f. 

Naturv. Bd. 6. — p. 158. - • - 

Staurophora vitrea M. Sars 1863. Geol. og zool. lagttag. . . . Reise i Trondhjems Stift — Ibid. 1863. 

- P- 339- . ,, . ^ . . „.,..,. 

— Keithii Peach 1867. ' " ■■-"■■■■ 

Staurostoma arctica Haeckel 1879. System der IMedusen. — p. 131. • "- . 

Thaumantias mclanops Mc Intosh 1890. Notes from the St Andrews Mar. Lab. — Ann. Mag. Nat Hist 

Ser. 6. Vol. V. — p. 40. PI. 8. ' ' " 

Staurophora falklandica Browne 1907. Revision of the .. Laodiceidte. — Ann. Mag. Nat Hist Ser. 7. 

Vol. XX. — p. 472. 

— — Browne 1908. Medusae, Scottish Nat Antarct. Exped. — Trans. R. Soc. Edinb. 

Vol. XLVI. Part II. — p. 235. Pl. I, fig.s. 1—7. 

— discoidea Kishinouye 1910. Some Medusae of Japanese Waters. — Journ. Coll. Sci. Imp. 

Univ. Tokyo. Vol. 27. — p. 29. 

The genus Staurophora was established and the species luerteu.u'i wa.s described by Brandt 
from drawings and notes of Mertens, who had collected this interesting medusa in the northern 
Pacific during his circumnavigation. L. Agassiz (1849) gave a new description of the genus, 
based on several specimens from Boston Harbour, North America. Agassiz rightly referred his speci- 
mens to the genus Staurophora Brandt, but established a new species, Staurophora lacitiiata. The de- 
scription given by Agassiz is very thorough and clear. He has not, however, observed the cordyli, 
and none of his specimens were full-grown; later investigations, therefore, have occasioned certain 
alterations of the description of the sj^ecies. The species is now so well known that it is unnecessary 
to give a general description in this place. Maas (1893) ^"*^^ Hartlaub (1897) have demon.strated 
that it is unreasonable to separate Staurophora arctica from the genus Staurophora and place it in a 
proper genus Staurostoma; Haeckel (1879) even placed the two genera within two different families 
at the same time as he observed that they were uearlj- related. 

With regard to the systematical positioii there can be no doubt but that the nearest relatives 
of Staurophora are the genera Laodicca and Ptychogena. iMayer (1910), liowever, separates the genus 
widely, fr9ni . these genera and places it within the _faraily Eucopidce. on account of the presence of 



.Q MEDUSA. I. 



marginal vesicles. These have been described by Linko {1900, p. 4. Taf. II, Fig. 22—25). The marginal 
vesicles are described as being very small and numerous, one inside each of the tentacles, situated in 
the ectoderm on the subumbrellular side of the bell inside the circular vessel, just above the suppor- 
ting lamella of the velum. The structure of the single vesicle could not be examined thoroughly 
"wegen der schlechten Conservierung" (p. 5). Browne (1908) has tried to find these marginal vesicles, 
but he found no trace of such organs; it seems reasonable, therefore, to suppose that the vesicles, 
which Linko found is his, as he states himself, badly preserved material, have simply been due to 
destruction of the tissues. We must, iu any case, wait for new investigations of well-preserved material, 
before the presence of marginal vesicles in this species can be stated. I myself have sectioned a part 
of the bell margin of Staurophora without finding any vesicles, but, I admit, the material at my dis- 
posal is not well suited for such examination. 

In the paper quoted above Linko mentions the structure of the ocelli, and he states that 
within the same specimen we may find every transitional stage from a simple pigment-spot to a cup- 
shaped eye with a lens. 

The most interesting feature in this species is the structure of the mouth. Brandt was of the 
opinion that the animal had no mouth at all, but that the food was received through the lancet- 
shaped "arms" in a manner corresponding to the facts in a Rhizostoma. Agassiz, on the other hand, 
calls attention to the eminent extention of the mouth, the corners of the mouth being prolonged along 
the four arms of the "cross". M. Sars (1863, p. 339) had a similar apprehension. When Haeckel 
states as a featiire characteristic for ^^Stauyostoma arclica", that the outer half of the gonadial part is 
closed, this must undoubtedly be due to a mutual gluening of the folded edges of this part of the 
mouth ; such gluening has been observed by several authors and is also seen in some of the specimens 
examined by me. 

As the corners of the mouth extend as far outwards as the gonads, the latter may in some 
way be said to have their position on the walls of the "stomach". Hartlaub (1897) takes this as an 
argument of a near relationship to the Tiaridcp. I am more inclined to think that the large extent 
of the mouth in Staurophora is a secondary character, and Staurophora is hardly the genus among 
the LaodiceidcF which is nearest related to the Tiaridce. A clear picture of the manner in which the 
mouth in Stauropliora has to be understood, has been delivered by Browne (1907, p. 470): "If one 
were to slit open along the middle the enlarged portions of each radial canal of Laodicea pi/lchra, 
and imagine the cut margins to be the margins of a mouth, then the position of the mouth, stomach, 
and gonads would be similar to those of Staurophora. I think the mouth of Staurophora has arisen 
by the outgrowth of a central mouth along the enlarged portions of the radial canals of a Laodice- 
like medusa, and consequently those portions of the radial canals have been converted into a four- 
rayed stomach. The gonads have not changed their position, but in Staurophora they have lengthened 
slightly and meet in the centre of the cros.s". I quite agree with this apprehension. 

The hydroid generation is unknown; but quite young stages of the medusa have been obser- 
ved by A. Agassiz (1862, p. 2, and 1865, p. 136) and Hartlaub (1897, p. 487), who have been able to 
follow the development so far that the species might be identified with certainty. — The first develop- 
mental stages of the egg have been observed by Wagner (1885, p. 80— 81). — Hargitt (1904, p. 43) 



MEDUSA. I. .J 



has demonstrated that the development of the eggs takes place in the genital folds, and that the 
larv£e leave these folds in the shape of actinulae. 

It is beyond all doubt that the species Staurophora vitrea Sars, Staiirophora Keithii Peach, and 
Sfaurostoma arctica Haeckel are identical with Stauropkora laciniata Agassiz. Since Bigelow (1913, 
p. 27) has seen a number of specimens from the same regions, where Mertens found the medusa; 
described by Brandt as Stauropkora merleiisii\ and has had the opportunity of comparing these 
specimens from the Pacific with specimens from the Atlantic, it ma\- be stated definiteh- that the species 
of Brandt and Agassiz are identical. The Staurophora dtscoidea described by Kishinouye (1910) is 
only separated from mertensii "by the more numerous lateral folds of the genital gland", the number 
of which was 17 in inerfensii. The description shows that this Japanese medusa in no respect differs 
from the Atlantic form of Staurophora. Thus all Staurophora from the northern seas belong to one 
and the same species, Staurophora uterft'iisu' Brandt. — In a paper, published in Danish (1914, p. 420), 
I have stated that Staurophora falklatidtca Browne also belongs to the same species. This fact will 
be further demonstrated below. 

Van h of fen mentions this species from the Atlantic outside the Ba\- of Biscay and from the 
Indian Ocean (1911, p. 219), further from the southern Atlantic between Trinidad and St. Helena and 
north-east of St. Paul (191 2, p. 366). In the last-named paper he also describes a new species, Stauro- 
phora aitfarctica from the antarctic Sea. I feel convinced that none of these medusae belong to the 
genus Staurophora. The specimens were all quite small, and Vanhoffen found that they agreed 
with Hartlaub's description of the young Staurophora from Heligoland. Common for the latter and 
Vanhoffeu's small medusa; is a general likeness to a young Tiarid. The medusic from the Indian 
Ocean (and the Bay of Biscay) are r — 18 mm wide with 4 — 64 tentacles. The 3 weeks old specimens 
described by Hartlaub were 10 mm high and a little broader, though far from iS nuu, and they had 
already more than 100 tentacles and, besides, a number of cordyli; the latter are not found in \' an- 
il of feu's meduste. In Hartlaub's specimens no traces of gonads were yet visible; \'anhoffen, 
on the other hand, mentions visible traces of gonads as grooves in the walls of the stomach in some 
of the specimens from the Indian Ocean (he does not state how iuan\- specimens or what sizes) as 
well as in the specimen from the southern Atlantic, which was only 5 mm high. Vanhoffen rightly 
calls attention to the fact, that the gonads being developed as grooves in the walls of the stomach is 
a feature pointing towards the Tiaridcr. But in Staurophora the gonads are not placed in grooves, but 
in lateral extensions developed along the line b\ which the cross is attached to the subumbrella. 
F'inally, Vanhoffen states that the specimens from the Indian Ocean (and the Bay of Biscay) are 
provided with ocelli on the outer (abaxial) side of the tentacular bulbs. This statement might 
possibly be due to a slip of the pen or a misprint; but in the figure of the medusa from the southern 
Atlantic (1912, Taf. XXV, fig. 3) the ocelli are clearly drawn as being abaxial. Altogether, I feel sure 
that the meduste, referred by Vanhoffen (in 1911 as well as in 1912) to Staurophora lacifiiafa, are 
really some kind of young Tiaridce. The same is undoubtedly the fact with regard to ''Staurophora 
antarctica". This medusa is 10 mm in diameter and has 8 tentacles; the stomach is deep brown with 
groove-shaped gonads. 

The Ingolf-ExpcJition. V. S. ^ 



42 



MEDUSA. I. 



In the following I am going to present some scattered morphological observations, made on 
the material of Staurophora mcrtensii from the North-Atlantic area, examined by me. 

The lower, free margin of the folded mouth-edge is sharply turned outwards as in Laodicea 
and Ptychogeiia. 

In full-grown specimens the gonadial folds are more highly developed in the middle part of 
the cross-arms than in the proximal and distal parts, each cross-arm thus being narrowly lancet- 
shaped. The primary lateral folds have usually 4 — 6 secondary folds, more seldom 7 or more. In middle- 
sized specimens the primary folds have, as a rule, the same number of secondary folds as in full-grown 
specimens, but as the sexual products are not fully developed, and the walls accordingly are thinner, the 
secondary folds do not come into contact, but are separated by open spaces. During growth of the animal, 
new primary folds are formed intermediary between the e^^isting ones. The lateral folds are flattened 



T a li 1 e I \'. Dimensions of some specimens of Staiiri>phora mcrtensii 
from Greenland and Iceland. 









Length of 




Locality 
number 


Diameter of 

specimens, 

cm 


Largest 
breadth of 
cross-arms. 


narrow part 

of radial 

canals. 


Number of 
tentacles 






mm 


mm 




3 


4'/2 


IV4 


3"^ 




2 


about 5 


IV'4 


4 




3 


5'A 


2 


4 




— 


7 




5 


about 1000 


5 


8 


3 


5 


more than 1200 


— 


9 


4V2 


6 


about 1100 


— 


9 


2V^ 


5 


— 1400 


— 


10 


5 


6 


— 1400 


— 


II 


7 


6 


— 1400 


~ 


about 12 


8 


9- 10 


— 4400 ■ 



on their upper (umbrellular) side, but they are only fastened to the subumbrella by narrow branched 
Hnes (see Plate II, fig. 9, presenting some lateral folds seen from the aboral side after being carefully 
loosened from the subumbrella). 

The largest breadth of the cross-arms and the length of the distal parts of the radial canals, 
free of gonads (the "proper" radial canals) have been measured on some specimens from Greenland 
and Iceland. The results are presented in Table IV, in which I have also given the number of tent- 
acle.s. Tlic numbers of localities will be found in the list of material below. The specimens are arranged 
according to the size. 

In larger .specimens the peripheral part of the exumbrella is provided with numerous deep, 
sharp,- radiating furrows of very different length, thougli rarelv more than 10 mm long; the number 
of furrows is variable, one being found off every second or fourth of the tentacles (see Plate I, fig. 9). 

The tentacles (Plate I, fig. 9; Plate II, fig. 10) are hollow. The basal bulbs are conical; the 
ectoderm of the bulb is somewhat thickened, particularly on the adaxial side (Plate II, fig. 10). Every 



MEDUSA. I. ., 

43 



tentacle bears, on its abaxial side, a narrow, pointed, entodermal spnr, penetrating into the gelatinous 
substance close to the exumbrellular side (Plate II, fig. ioi. The distal part of the tentacle is, as a rule, 
spiralh- coiled. The tentacles are very numerous and, frequently, so densely crowded that, owing to 
the lack of room, they seem to be situated in somewhat different height on the bell-margin. 

In the young medusa the tentacles are developed in a certain regular succession, as demon- 
strated by A. Agassiz (1863). In older specimens we find tentacles of every .size in quite irregular 
succession. We may find, howevei, fully developed tentacles and quite young tentacles almost regularly 
alternating, particularly in very large specimens. Wlien the tentacles are very densely crowded, these 
young tentacles may be quite thin and delicate, almost like cirri, and ai)parcntly situated a little inside 
the fully developed tentacles. By closer examination, however, we will ahva\s find that the small 
tentacles are not quite alike, but that some of them are a little larger tlian tlie others and approach 
the fully developed tentacles in shape. When there is a little better room, the young tentacles are 
placed in the same row as the others and have a fairly broad ba.se, clearly indicating that they are 
real tentacles, not cirri; beside.^ a spur is very soon developed. Ocelli, on the otlier hand, are usually 
not developed until tlie tentacle lias reached a fairly considerable size. The nearl>- regular alternation 
of small tentacles without ocelli and large tentacles witli ocelli was the feature, on which P)rowne 
(1908, p. 235) based the species Staitropliora falklaiidica. As exactly the same feature is frequently found 
in northern specimens of Sfa/trop/iora, and as S/a/tyop/ioya falklaJidica in all other respects has a 
complete likeness to the northern S/a/inip/iora ntcrtensii, tliere can be no doubt as to the identity of 
the two forms. Browne himself remarks (p. 236): "It is rather a risky point, I admit, on which to 
base the character of a new species, as there is the probabilit}' of the small tentacles developing into 
full-sized tentacles with ocelli". 

As a rule, there is one adaxial ocellus on the base of each of the tentacles with the exception 
of the quite young ones. Some irregularit\- may, iiowever, be found. In 4 specimens from North-Iceland 
("Thor" Stat. 220(04), Loc. No. 5) the ocelli are arranged in the following manner: i) Diameter of the 
specimen 8 cm, ocellus on about every 4th of the tentacles; 2) diameter 9 cm, ocellus on about every 
3rd — 4th of the tentacles, not seldom two ocelli on one tentacle; 3) diameter 10 cm, ocellus on every 
3rd —4th of the tentacles; 4) diameter 11 cm, ocellus on almost every 2nd of the tentacles. Sometimes 
the pigment of the ocelli may disappear on account of the preservation, and we cannot exclude the 
possibility that this has happened in the specimens mentioned above, as far as the tentacles now 
destitute of ocelli are concerned. 

In this species the number of cordyli (Plate I, fig. 9; Plate III, fig. 7) is always equal to the 
number ot tentacles, the cordyli regularly alternating with the latter, situated in a row a little inside 
the row of tentacles. The peduncle is thin and lengthened, the distal part is fairly much swollen. Witli 
regard to the question of their transformation into tentacles, see above, p. 5. 

The velum is very narrow, 1-2 mm broad. 

According to the literature this species may attain a size of 20 cm in diameter. Among the 
material in hand no specimen is more than about 12 cm wide; this is probably due to the collectors 
having not, for lack of room, preserved the largest of the specimens fomid. I remember having seen 
numerous very large individuals, far more than 12 cm wide, in the waters round Iceland in 1908. 



44 



MEDUSA I. 



Material (see Chart IV). 

Greenland: 

i) — Egedesminde. Bergen da 1. — i specimen, destrncted with osmic acid. 

2) — Egedesminde. Transtedt. — i specimen, abont 5 cm wide. 

3) — Lat. 66°o6' N., Long. 54°27' W., Davis Strait, off Southern Stromfjord. August 28th 1908. 
Ringtrawl, 150 m wire. "Tjalfe" stat. .223. — 2 specimens, 4.5 and 5.5 cm wide. 




Chart IV. l'"inds of Staurophora mirtcmi: Brandt in the northern Atlantic. O and hatching: 
Occurrence according to the Uterature. 



4) — Lat. 66°oi' N., Long. 54°23' W., Davis Strait, off Southern Stromfjord. August 2Sth 1908. 
Ringtrawl, 150 ni wire. "Tjalfe" stat. 225. — A few specimens, not preserved. 

I celand: 

5) — Lat. 65°3i.5' N., Long. i3°32' W., East-Iceland. July 29th 1904. Depth 55 m. 60 m wire. 
"Thor" stat. 220(04). — 5 specinien.s, diam. 8, 9, 9, 10, 11 cm. 

6) — Near Gijotnaes, Melrakka. July 26th 1896. "Ingolf Exp. — i specimen, about 7 cm wide. 



MEDUvS^. I. ,- 



7) — Axarfjord. August i2th 1903. "Beskytteren", Gemzoe. — i specimen, torn, probably 
about 6 cm wide. 

8) -^ Lat. 66°i4' N., Long. I7°28' W., vSkjalfandifjord. July 21st 1904. "Thor" stat. 208(04). — 
Pieces of several specimens. 

9) — Lat. 66°i5' N., Long. 23°30' W., off Lsafjord. June i5tli 1903. "Thor" staL 134(03). — One 
specimen, in the collection of the Plankton Laboratory, Copenhagen. 

10) — Dyrefjord. July 14th 1892. Lundbeck. — i specimen 7 cm wide. 

11) — Lat. 64°o6' N., Long. 23°i4' W., Faxebugt. July 2nd 1908. Depth 98 m. 65 m wire. "Thor" 
stat. 45 (08). — A piece of the bell-margin with the outer part of a radial canal of a large specimen. 

12) — Lat. 63°5i' N., Long. :6°29' W., ^^yi Bugt. August 9th 1904. Depth 40 m. "Beskytteren", 
Gemzoe. — Pieces of a large specimen, which must have been about 12 cm wide. On a 5 cm long 
piece of the bell margin there are 115 well-developed and as many young and very thin tentacles; 
the specimen must, accordingly, have had several thousands of tentacles. 

Faeroe Islands: 

13) — Thorshavn. August i8th 1895. "Ingolf Exp. — Small pieces of several individuals of 
different size and stage of development, treated with Flemmings solution. 

Norway: 

14) — Borgundfjord near Aalesund. June 25th 1902. "Michael Sars", Ad. vS. Jensen. — Several 
torn specimens, not very large. 

North Sea: 

15) — Lat. 59°46' N., Long. o°07' W., east of the north-point of Scotland. May 7th 1905. 130 m 
wire. "Thor" stat. 21 (05). — In the collection of the Plankton Laborator>-, Copenhagen. 

With the exception of the specimens from the localities 4, 9, and 15 the whole of the material 
here mentioned is in the Zoological Museum of Copenhagen. 

F u r t h e r D i s t r i b u t i o n : 

North AtlanticArea, eastern part: 

Spttzbergeii (Haeckel 1879, p. 131). 

Barents Sea (Linko 1904 a, p. 16 and 1904b, p. 218). In the eastern (coldest) part of the Barents 
Sea Staurophom is common in the open sea as well as in the neighbourhood of the coast; in the 
western part it is somewhat scarce in the open sea, and in the summer it is almost never found near 
the coast. In the unusually cold summer of 1899 it was, however, numerous in Kolafjord and in Eka- 
terin Harbour. Towards the end of the year, on the other hand, it occurs regularly in the neighbour- 
hood of the coast, and it seems then to breed in this region, young medusae being found here during 
the first half-part of the \ear; towards the spring these young medusae emigrate towards the North. 

White Sea (Wagner 1885, p. 80; Birula 1896, p. i6). Wagner found several .specimens, 6— 
12 cm wide, in the Solowetsky Bay in July 1880. 

Norway. According to M. Sars (1851, p. 158 and 1863, p. 339) the species is not rare at the 
coast of Finmarken, where Sars found two .specimens, 16 cm wide, in Oxfjord and Havosund m the 



46 MEDUS.E. I. 



summer of 1849. Sars also found a single specimen near Christiansund. Broch (1905, p. 7) records it, 
though with some doubt, from Puddefjord at Bergen. 

East coast 0/ Scotland. Peterhead, May-June (Peach 1S68, p. 97); St. Andrews (Mc In tosh 
1890, p. 40). 

Heligoland. Young specimens about April ist, full-grown specimens at the end of May 1895 
(Hartlaub 1897, p. 484 ff). 

North Atlantic area, western part: 

West coast of Greenland. All .specimens hitherto known from Greenland (Levin sen 1892, 
p. 145; Kramp 1913, p. 269 and 1914, p. 420) have been mentioned above. 

East coast 0/ North America. New Foundland: Fogo Island, at the surface in July (Bigelow 
1909b, p. 307). — New England: Grand Manan (Stimpsou-1854, p. 11; Fewkes 1888a, p. 233); East- 
port (Verrill 1872, p. 6); Massachusetts Bay (L. Agassiz 1849, P-30o^f-; A. Agassiz 1865, p. 136); 
Woods Hole (Hargitt 1902, p. 553 and 1904, p. 43— 44); Fishers Island Sound (Verrill 1875, p. 43); 
Frye's Island, New Brunswick (Fewkes 1888a, p. 233). Bigelow, in a series of papers (1914a, 
p. 123 — 124; 1914b, p. 12; 1914 c, p. 407; 1915, pp. 267, 273, 274,-319, 320), has dealt with the occurrence 
of this species off the coasts of New England. It appears from his statements that Stajirophora tner- 
tnisii is common north of Cape Cod, whereas sout of this point it occurs only occasionally, and then 
only in the spring. In the Gulf of Maine it is "a constant inhabitant", though it occurs particularly 
in the neighbourhood of the shore; Bigelow states that this is not surprising ''because it is 
undoubtedly neritic" (1914 a, p. 124). Young specimens are found at the end of April or at the begin- 
ning of May; thus many very young stages were found in Gloucester Harbour on May 3rd 1913 (op. 
cit. 1914 c); these young stages probably "have passed through the fixed stage in the near neighbor- 
hood". On May 17th of the same )ear several specimens were found, about 2 inches (5 cm) wide. 
Grown-up individuals are found in June, July, and August. During the investigations in Jul}- and 
August 1913 (op. cit. 191 5) Stanrophora occurred in the whole of the Gulf of Maine, but not south of 
Cape Cod. Hargitt (1902 and 1904) has found the species in considerable numbers at Woods Hole, 
but he remarks: "Its occurrence seems to be somewhat erratic, however, as I have taken specimens 
l)Ut twice within recent year.s" (1904, p. 44). 

The American investigations show that Stanrophora nicrtensii is indigenous to the Gulf of 
Maine and breeds here; further that in the said area its occurrence is not limited to the cold water; south 
of Cape Cod, on the other hand, it is only an occasional visitor, and in the hot season of the year it 
is quite absent from that area. 

Northern Pacific: 

Norfolksound ; in the Ocean as far as Unalaschka and between Sitka and the Aleutean Is- 
lands (Brandt 1835); Dutch Harbor and Prince William vSound, Alaska (Bigelow 1913); Sachalin 
and northern part of Japan (Kishinouye 1910). In .short, it occurs along the southern coast of Alaska, 
but not off the west coast of North America south of Sitka; further alou" the coast of Asia as far 
south as the northern part of Japan. 

Falkland Islands: 
: January 7th 1903 (Browne 1907, p. 473 and 1908, p. 235). 



MEDUSA, r. .^ 



If we compare the statements of the literature with the experiences derived from the material 
dealt with in the present paper, we will get the following general picture of the distribution and oc- 
currence of Stanroplwra mcrtcnsir. In the Atlantic as well as in the Pacific the main distribution of 
the species is within the arctic region; in both of these oceans, however, the species may penetrate 
fairly far southwards into boreal regions, though decreasing in frequency. It is exceedingly numerous 
off the northern and eastern coasts of Iceland, but somewhat scarce off the southern coast, which is 
washed by the water of the Gulf Stream. In the Barents vSea it mainly keeps itself in the northern 
and eastern cold parts, whereas it only penetrates to the south-western part, near the Murman coast, 
in the autumn or in very cold summers. It does not seem to be scarce in the fjords of Finmarken, 
but only at a few occasions has it been met with at more southerly parts of the Nprwegian coast. 
The occurrence of quite \oung specimens at Heligoland demonstrates that the species may live and 
breed in the North Sea, but it is apparently very rare in that area. — Off the Atlantic coast of North 
America it is indigenous in the Gulf of Maine, but south of Cape Cod it is only met with occasion- 
ally and only in the spring montlis. — In the eastern part of the Pacific its occurrence is limited to 
the coast of Alaska, in the western part it penetrates as far southwards as extends the influence of 
the cold Kamtschatka Current. 

Everywhere the species is a well-marked coastal-water form. Particularly it is worth mention- 
ing that all finds of )oung individuals, hitherto known, have been made very near the shore. Young 
specimens are always found in the spring, April — Mav, whereas the grown-up specimens are mainly 
found in August or later (cfr. the statements of the occurrence in the Barents Sea). There can be no 
doubt, but that Staurophora has a neritic, fixed hydroid-generation, which hibernates, and from which 
the young medusae are deliberated in the spring. 

Of great interest is the bipolar distribution. The medusa described by Browne from the 
Falkland Islands was found at the beginning of January; thus also in the Antarctic the species is a 
summer-form. 

Family Thaumantiadae. 
Genus Melicertum L. Agassiz. 

This genus has an interesting but not very joyous history, in .so far as it has given ri.se to 
much confusion owing to a peculiar want of criticism by some otherwise prominent authors. Haeckel 
(1879), as the first, has called attention to this confusion and iinravelled the history of the genus. But 
at the same time Haeckel introduced the generic name Mdiccrtidiitm for a species, which was later 
found to belong to the same genus, which L. Agassiz called J/f//"cr;-//<';//, and thus the question rose, 
which of these two names ought to be used as the correct one. Browne (1905) and Mayer (1910) 
have discussed this question and thereby given new accounts of the history of the genus. As the said 
authors arrive to opposite results with regard to the question of the correct name, I have thought it 
worth while to deal with the matter once more from a historical point of view, in order to make out 
my position to that question. 

The Medusa campanitla, as described by Fabricius (Fauna groenlandica, 1780, p. 366). had 



48 



MEDUSA. I. 



4 radial canals and a small number of tentacles, as it appears from the rather short and vague descrip- 
tion. — Peron and Lesueur (1809, p. 352) quoted the description of Fabricius and referred the 
species to the genus Melucrta^ established by these authors, and written by Oken (1815) Meh'cerium^. 
Lamarck (i8i6, p. 508) called the species with the name of Diancpa campatmla. — Eschscholtz 
(1829, p. 105 — 107 has 4 species of Gen. Melicertjmi Oken, all of which have 4 radial canals: M. cainpa- 
njila Fabricius, M. campanulainm Chamisso, M. penicillatitni, and M. pusilliim Swartz. — Melicertum 
catnpamtla is mentioned again by Oken (1835, p. 226) with reference to the description of Fabricius. 
— Lesson (1843, p. 313) called it Campanella Fabricu\ and in Morch's list of the Acalephs of Green- 
land (Morch 1857, p. 95) Fabricii medusa is included as Campanella campanula. 

In 1835 (p. 24) M. Sars described a medusa, Oceania octocoslata, with 8 radial canals and 
numerous (40 — 60) tentacles, found at the coast of Norway. JThe next year the same species was figured 
by Ehrenberg (1836, Taf. VIII, figs. 5 — 7), who does not seem to have known Sars's description. 
Ehrenberg gives no description of the animal, but his figures are very good and leave no doubt as 
to the identity of the species. It is peculiar, therefore, that Ehrenberg, in the explanation of the 
plates, p. 77, refers this 8-rayed medusa to Melicertum campamtlatutn Eschscholtz, which, as mentioned 
above, has 4 radial canals. — Some specimens from the north coast of Ireland were identified by Wm. 
Thompson (1S43, p. 281) as Melicertitm campaimlatum Ehrenberg. — Sars's medusa was included 
m the work of Lesson (1843, p. 312) as Aeqiiorea octocostata^ and in Forbes's Monograph (1848, 
p. 30, Plate I\', fig. i) as Stomobrachium octocostatitm. 

A medusa related to Oceania octocostata Sars was found in Massachusetts Bay, North America, 
by L. Agassiz. It is quite unintelligible, that Agassiz should refer this medusa to the genus Meli- 
cerlum Oken and identify it y^iih. Medusa campanula Fabricius. With Agassiz the genus Melicertum 
gets an entirely new meaning and is even used (as appears from the note on p. 352) as the type 
of a family MelicertidcE.^ which is characterised by the possession of 8 radial canals. Agassiz referred 
four species to his genus Melicertum: i) M. campanula Fabricius; 2) M. pusilliim Eschscholtz (which 
is incorrectly identified with Oceania octocostata Sars, Melicertum campanulatitm Ehrenberg, Stomo- 
hrachium octostatiim Forbes etc.); 3) M. campanulatitm Eschscholtz (uon Ehrenberg); 4) M. georgicmn 
A. Agassiz, shortly described in a footnote on p. 349. — A. Agassiz (1865, p. 130—134) gives a 
thorough and clear description of Melicertum campatmla sensu L. Agassiz, but A. Agassiz, like his 
father, regards the species as identical with Medusa campanula Fabricius. Browne (1905, p. 765) 
rightly remarks : ^'Melicertum has realh- become a new genus, and with a new type species, M. campa- 
nula A. Agassiz (uon Fabricius)". 

Since the forthcoming of the work of Agassiz the American species has always been called 
by the name of Melicertum campanula, and when that name is used for medusae from the Atlantic 
coa.st of North America, any doubt of the identity is excluded. But the mistake of Agassiz has been 
the cause, why the species for a long time to follow was recorded as occurring at the coast of Green- 

' III the front-list of contents in Ok en's Lehrl)ucli der Zoologie, erste .\bth , Melicertum is mentioned as the fourth 
genus of "Walnimanete", and reference is given to p 125. .\lso in the alphabetic register in the rear of the book Melicertum 
IS found with reference to p. 125. But if we look at p. 125, we will find that "Walnimanete" only includes three genera. 
Group D of Gen. Charybdea is characterised as follows: "Stiel verlangerte Magen, lost sich in viele Hare auf — MelicertJ'. 
The name Melicertum is not found, nor the specific name campanula. 



MEDUSAE. I. ,^ 
49 



land; Liitken (1875, p. 188) who was not aware of the mistake, included Melicerliim campanula in 
his list of the medusae of Greenland, and from the authority of Liitken it was likewise included in 
the lists published by Winther (1880, p. 274) and Fewkes {1888b). 

Haeckel (1879, p. 136) was the first to see the mistake, and he sharply criticises Agassiz, 
because he referred the American 8-rayed medusa to Meliccrtniii campanula (Fabricius), Eschscholtz, 
Oken, as also because he referred Oceania octocostata vSars to Meliccrtum pusillum Eschscholtz. 
Haeckel is of opinion, however, that tlie generic name Melicerlum Agassiz, non Oken and Esch- 
scholtz. ought to be retained for the species campanula and georgicutn^ because "Agassiz wirklich 
die erste gute Beschreibung und Abbildung . . . gegeben und die acht Radial-Canjile als Familie- 
Character hervorgehoben hat". 

The European form, on the other hand, is elevated by Haeckel to be the type of a new- 
genus, Melicertidiitui, on account of the presumed presence of "marginale Kolben (oder Cirren)" (op. 
cit. p. 137). As a matter of fact, Haeckel himself lias not seen this medusa, but his meditations 
are based on the previous descriptions and, obviously, mainly on the figures of Ehrenberg. These 
figures exhibit a series of short tentacles alternating with the long ones, but on account of the way in 
which these short tentacles were drawn by Ehrenberg. Haeckel got the apprehension that they 
were clubs. — After Haeckel (1879) the European form has, mostl\-, been recorded as Melicertidium 
octocosfatinn\ also Hartlaub (1894, p. 192) uses that name at the same time as he states that the 
medusa has no marginal bulbs but small tentacles as numerous as the common tentacles, and that 
this is